diff --git a/composer.json b/composer.json
index 87bd8a1..3c7690a 100644
--- a/composer.json
+++ b/composer.json
@@ -34,7 +34,7 @@
         "react/stream": "^1.2"
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.6 || ^5.7",
+        "phpunit/phpunit": "^9.6 || ^7.5",
         "react/async": "^4 || ^3",
         "react/promise-stream": "^1.4",
         "react/promise-timer": "^1.10"
diff --git a/phpunit.xml.legacy b/phpunit.xml.legacy
index a018d7a..0086860 100644
--- a/phpunit.xml.legacy
+++ b/phpunit.xml.legacy
@@ -2,7 +2,7 @@
 
 <!-- PHPUnit configuration file with old format for legacy PHPUnit -->
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/5.7/phpunit.xsd"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/7.5/phpunit.xsd"
          bootstrap="vendor/autoload.php"
          colors="true">
     <testsuites>
diff --git a/tests/ConnectionTest.php b/tests/ConnectionTest.php
index 49d53e2..2ef1e5c 100644
--- a/tests/ConnectionTest.php
+++ b/tests/ConnectionTest.php
@@ -2,6 +2,7 @@
 
 namespace React\Tests\Socket;
 
+use React\EventLoop\LoopInterface;
 use React\Socket\Connection;
 
 class ConnectionTest extends TestCase
@@ -9,7 +10,7 @@ class ConnectionTest extends TestCase
     public function testCloseConnectionWillCloseSocketResource()
     {
         $resource = fopen('php://memory', 'r+');
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $connection = new Connection($resource, $loop);
         $connection->close();
@@ -20,7 +21,7 @@ public function testCloseConnectionWillCloseSocketResource()
     public function testCloseConnectionWillRemoveResourceFromLoopBeforeClosingResource()
     {
         $resource = fopen('php://memory', 'r+');
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addWriteStream')->with($resource);
 
         $onRemove = null;
diff --git a/tests/ConnectorTest.php b/tests/ConnectorTest.php
index 039d7cb..dd2f87b 100644
--- a/tests/ConnectorTest.php
+++ b/tests/ConnectorTest.php
@@ -2,8 +2,11 @@
 
 namespace React\Tests\Socket;
 
-use React\Socket\Connector;
+use React\Dns\Resolver\ResolverInterface;
+use React\EventLoop\LoopInterface;
 use React\Promise\Promise;
+use React\Socket\Connector;
+use React\Socket\ConnectorInterface;
 
 class ConnectorTest extends TestCase
 {
@@ -19,12 +22,12 @@ public function testConstructWithoutLoopAssignsLoopAutomatically()
         $ref->setAccessible(true);
         $loop = $ref->getValue($connectors['tcp']);
 
-        $this->assertInstanceOf('React\EventLoop\LoopInterface', $loop);
+        $this->assertInstanceOf(LoopInterface::class, $loop);
     }
 
     public function testConstructWithLoopAssignsGivenLoop()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $connector = new Connector([], $loop);
 
@@ -36,12 +39,12 @@ public function testConstructWithLoopAssignsGivenLoop()
         $ref->setAccessible(true);
         $loop = $ref->getValue($connectors['tcp']);
 
-        $this->assertInstanceOf('React\EventLoop\LoopInterface', $loop);
+        $this->assertInstanceOf(LoopInterface::class, $loop);
     }
 
     public function testConstructWithContextAssignsGivenContext()
     {
-        $tcp = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $tcp = $this->createMock(ConnectorInterface::class);
 
         $connector = new Connector([
             'tcp' => $tcp,
@@ -58,10 +61,10 @@ public function testConstructWithContextAssignsGivenContext()
 
     public function testConnectorUsesTcpAsDefaultScheme()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $promise = new Promise(function () { });
-        $tcp = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $tcp = $this->createMock(ConnectorInterface::class);
         $tcp->expects($this->once())->method('connect')->with('127.0.0.1:80')->willReturn($promise);
 
         $connector = new Connector([
@@ -73,10 +76,10 @@ public function testConnectorUsesTcpAsDefaultScheme()
 
     public function testConnectorPassedThroughHostnameIfDnsIsDisabled()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $promise = new Promise(function () { });
-        $tcp = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $tcp = $this->createMock(ConnectorInterface::class);
         $tcp->expects($this->once())->method('connect')->with('tcp://google.com:80')->willReturn($promise);
 
         $connector = new Connector([
@@ -89,13 +92,13 @@ public function testConnectorPassedThroughHostnameIfDnsIsDisabled()
 
     public function testConnectorWithUnknownSchemeAlwaysFails()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $connector = new Connector([], $loop);
 
         $promise = $connector->connect('unknown://google.com:80');
 
         $promise->then(null, $this->expectCallableOnceWithException(
-            'RuntimeException',
+            \RuntimeException::class,
             'No connector available for URI scheme "unknown" (EINVAL)',
             defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
         ));
@@ -103,7 +106,7 @@ public function testConnectorWithUnknownSchemeAlwaysFails()
 
     public function testConnectorWithDisabledTcpDefaultSchemeAlwaysFails()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $connector = new Connector([
             'tcp' => false
         ], $loop);
@@ -111,7 +114,7 @@ public function testConnectorWithDisabledTcpDefaultSchemeAlwaysFails()
         $promise = $connector->connect('google.com:80');
 
         $promise->then(null, $this->expectCallableOnceWithException(
-            'RuntimeException',
+            \RuntimeException::class,
             'No connector available for URI scheme "tcp" (EINVAL)',
             defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
         ));
@@ -119,7 +122,7 @@ public function testConnectorWithDisabledTcpDefaultSchemeAlwaysFails()
 
     public function testConnectorWithDisabledTcpSchemeAlwaysFails()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $connector = new Connector([
             'tcp' => false
         ], $loop);
@@ -127,7 +130,7 @@ public function testConnectorWithDisabledTcpSchemeAlwaysFails()
         $promise = $connector->connect('tcp://google.com:80');
 
         $promise->then(null, $this->expectCallableOnceWithException(
-            'RuntimeException',
+            \RuntimeException::class,
             'No connector available for URI scheme "tcp" (EINVAL)',
             defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
         ));
@@ -135,7 +138,7 @@ public function testConnectorWithDisabledTcpSchemeAlwaysFails()
 
     public function testConnectorWithDisabledTlsSchemeAlwaysFails()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $connector = new Connector([
             'tls' => false
         ], $loop);
@@ -143,7 +146,7 @@ public function testConnectorWithDisabledTlsSchemeAlwaysFails()
         $promise = $connector->connect('tls://google.com:443');
 
         $promise->then(null, $this->expectCallableOnceWithException(
-            'RuntimeException',
+            \RuntimeException::class,
             'No connector available for URI scheme "tls" (EINVAL)',
             defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
         ));
@@ -151,7 +154,7 @@ public function testConnectorWithDisabledTlsSchemeAlwaysFails()
 
     public function testConnectorWithDisabledUnixSchemeAlwaysFails()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $connector = new Connector([
             'unix' => false
         ], $loop);
@@ -159,7 +162,7 @@ public function testConnectorWithDisabledUnixSchemeAlwaysFails()
         $promise = $connector->connect('unix://demo.sock');
 
         $promise->then(null, $this->expectCallableOnceWithException(
-            'RuntimeException',
+            \RuntimeException::class,
             'No connector available for URI scheme "unix" (EINVAL)',
             defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
         ));
@@ -167,10 +170,10 @@ public function testConnectorWithDisabledUnixSchemeAlwaysFails()
 
     public function testConnectorUsesGivenResolverInstance()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $promise = new Promise(function () { });
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->once())->method('resolve')->with('google.com')->willReturn($promise);
 
         $connector = new Connector([
@@ -183,14 +186,14 @@ public function testConnectorUsesGivenResolverInstance()
 
     public function testConnectorUsesResolvedHostnameIfDnsIsUsed()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $promise = new Promise(function ($resolve) { $resolve('127.0.0.1'); });
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->once())->method('resolve')->with('google.com')->willReturn($promise);
 
         $promise = new Promise(function () { });
-        $tcp = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $tcp = $this->createMock(ConnectorInterface::class);
         $tcp->expects($this->once())->method('connect')->with('tcp://127.0.0.1:80?hostname=google.com')->willReturn($promise);
 
         $connector = new Connector([
diff --git a/tests/DnsConnectorTest.php b/tests/DnsConnectorTest.php
index da2df86..11d1f2f 100644
--- a/tests/DnsConnectorTest.php
+++ b/tests/DnsConnectorTest.php
@@ -2,8 +2,10 @@
 
 namespace React\Tests\Socket;
 
+use React\Dns\Resolver\ResolverInterface;
 use React\Promise\Deferred;
 use React\Promise\Promise;
+use React\Socket\ConnectorInterface;
 use React\Socket\DnsConnector;
 use function React\Promise\reject;
 use function React\Promise\resolve;
@@ -19,8 +21,8 @@ class DnsConnectorTest extends TestCase
      */
     public function setUpMocks()
     {
-        $this->tcp = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
-        $this->resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $this->tcp = $this->createMock(ConnectorInterface::class);
+        $this->resolver = $this->createMock(ResolverInterface::class);
 
         $this->connector = new DnsConnector($this->tcp, $this->resolver);
     }
@@ -28,7 +30,7 @@ public function setUpMocks()
     public function testPassByResolverIfGivenIp()
     {
         $this->resolver->expects($this->never())->method('resolve');
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('127.0.0.1:80'))->will($this->returnValue(reject(new \Exception('reject'))));
+        $this->tcp->expects($this->once())->method('connect')->with('127.0.0.1:80')->willReturn(reject(new \Exception('reject')));
 
         $promise = $this->connector->connect('127.0.0.1:80');
 
@@ -37,8 +39,8 @@ public function testPassByResolverIfGivenIp()
 
     public function testPassThroughResolverIfGivenHost()
     {
-        $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('google.com'))->will($this->returnValue(resolve('1.2.3.4')));
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('1.2.3.4:80?hostname=google.com'))->will($this->returnValue(reject(new \Exception('reject'))));
+        $this->resolver->expects($this->once())->method('resolve')->with('google.com')->willReturn(resolve('1.2.3.4'));
+        $this->tcp->expects($this->once())->method('connect')->with('1.2.3.4:80?hostname=google.com')->willReturn(reject(new \Exception('reject')));
 
         $promise = $this->connector->connect('google.com:80');
 
@@ -47,8 +49,8 @@ public function testPassThroughResolverIfGivenHost()
 
     public function testPassThroughResolverIfGivenHostWhichResolvesToIpv6()
     {
-        $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('google.com'))->will($this->returnValue(resolve('::1')));
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('[::1]:80?hostname=google.com'))->will($this->returnValue(reject(new \Exception('reject'))));
+        $this->resolver->expects($this->once())->method('resolve')->with('google.com')->willReturn(resolve('::1'));
+        $this->tcp->expects($this->once())->method('connect')->with('[::1]:80?hostname=google.com')->willReturn(reject(new \Exception('reject')));
 
         $promise = $this->connector->connect('google.com:80');
 
@@ -58,7 +60,7 @@ public function testPassThroughResolverIfGivenHostWhichResolvesToIpv6()
     public function testPassByResolverIfGivenCompleteUri()
     {
         $this->resolver->expects($this->never())->method('resolve');
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('scheme://127.0.0.1:80/path?query#fragment'))->will($this->returnValue(reject(new \Exception('reject'))));
+        $this->tcp->expects($this->once())->method('connect')->with('scheme://127.0.0.1:80/path?query#fragment')->willReturn(reject(new \Exception('reject')));
 
         $promise = $this->connector->connect('scheme://127.0.0.1:80/path?query#fragment');
 
@@ -67,8 +69,8 @@ public function testPassByResolverIfGivenCompleteUri()
 
     public function testPassThroughResolverIfGivenCompleteUri()
     {
-        $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('google.com'))->will($this->returnValue(resolve('1.2.3.4')));
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('scheme://1.2.3.4:80/path?query&hostname=google.com#fragment'))->will($this->returnValue(reject(new \Exception('reject'))));
+        $this->resolver->expects($this->once())->method('resolve')->with('google.com')->willReturn(resolve('1.2.3.4'));
+        $this->tcp->expects($this->once())->method('connect')->with('scheme://1.2.3.4:80/path?query&hostname=google.com#fragment')->willReturn(reject(new \Exception('reject')));
 
         $promise = $this->connector->connect('scheme://google.com:80/path?query#fragment');
 
@@ -77,8 +79,8 @@ public function testPassThroughResolverIfGivenCompleteUri()
 
     public function testPassThroughResolverIfGivenExplicitHost()
     {
-        $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('google.com'))->will($this->returnValue(resolve('1.2.3.4')));
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('scheme://1.2.3.4:80/?hostname=google.de'))->will($this->returnValue(reject(new \Exception('reject'))));
+        $this->resolver->expects($this->once())->method('resolve')->with('google.com')->willReturn(resolve('1.2.3.4'));
+        $this->tcp->expects($this->once())->method('connect')->with('scheme://1.2.3.4:80/?hostname=google.de')->willReturn(reject(new \Exception('reject')));
 
         $promise = $this->connector->connect('scheme://google.com:80/?hostname=google.de');
 
@@ -93,7 +95,7 @@ public function testRejectsImmediatelyIfUriIsInvalid()
         $promise = $this->connector->connect('////');
 
         $promise->then(null, $this->expectCallableOnceWithException(
-            'InvalidArgumentException',
+            \InvalidArgumentException::class,
             'Given URI "////" is invalid (EINVAL)',
             defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
         ));
@@ -113,7 +115,7 @@ public function testConnectRejectsIfGivenIpAndTcpConnectorRejectsWithRuntimeExce
         });
 
         assert($exception instanceof \RuntimeException);
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         $this->assertEquals('Connection to tcp://1.2.3.4:80 failed: Connection failed', $exception->getMessage());
         $this->assertEquals(42, $exception->getCode());
         $this->assertNull($exception->getPrevious());
@@ -134,7 +136,7 @@ public function testConnectRejectsIfGivenIpAndTcpConnectorRejectsWithInvalidArgu
         });
 
         assert($exception instanceof \InvalidArgumentException);
-        $this->assertInstanceOf('InvalidArgumentException', $exception);
+        $this->assertInstanceOf(\InvalidArgumentException::class, $exception);
         $this->assertEquals('Invalid', $exception->getMessage());
         $this->assertEquals(42, $exception->getCode());
         $this->assertNull($exception->getPrevious());
@@ -155,10 +157,10 @@ public function testConnectRejectsWithOriginalHostnameInMessageAfterResolvingIfT
         });
 
         assert($exception instanceof \RuntimeException);
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         $this->assertEquals('Connection to tcp://example.com:80 failed: Connection to tcp://1.2.3.4:80 failed: Connection failed', $exception->getMessage());
         $this->assertEquals(42, $exception->getCode());
-        $this->assertInstanceOf('RuntimeException', $exception->getPrevious());
+        $this->assertInstanceOf(\RuntimeException::class, $exception->getPrevious());
         $this->assertNotEquals('', $exception->getTraceAsString());
     }
 
@@ -176,7 +178,7 @@ public function testConnectRejectsWithOriginalExceptionAfterResolvingIfTcpConnec
         });
 
         assert($exception instanceof \InvalidArgumentException);
-        $this->assertInstanceOf('InvalidArgumentException', $exception);
+        $this->assertInstanceOf(\InvalidArgumentException::class, $exception);
         $this->assertEquals('Invalid', $exception->getMessage());
         $this->assertEquals(42, $exception->getCode());
         $this->assertNull($exception->getPrevious());
@@ -186,7 +188,7 @@ public function testConnectRejectsWithOriginalExceptionAfterResolvingIfTcpConnec
     public function testSkipConnectionIfDnsFails()
     {
         $promise = reject(new \RuntimeException('DNS error'));
-        $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('example.invalid'))->willReturn($promise);
+        $this->resolver->expects($this->once())->method('resolve')->with('example.invalid')->willReturn($promise);
         $this->tcp->expects($this->never())->method('connect');
 
         $promise = $this->connector->connect('example.invalid:80');
@@ -197,10 +199,10 @@ public function testSkipConnectionIfDnsFails()
         });
 
         assert($exception instanceof \RuntimeException);
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         $this->assertEquals('Connection to tcp://example.invalid:80 failed during DNS lookup: DNS error', $exception->getMessage());
         $this->assertEquals(0, $exception->getCode());
-        $this->assertInstanceOf('RuntimeException', $exception->getPrevious());
+        $this->assertInstanceOf(\RuntimeException::class, $exception->getPrevious());
         $this->assertNotEquals('', $exception->getTraceAsString());
     }
 
@@ -208,7 +210,7 @@ public function testRejectionExceptionUsesPreviousExceptionIfDnsFails()
     {
         $exception = new \RuntimeException();
 
-        $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('example.invalid'))->willReturn(reject($exception));
+        $this->resolver->expects($this->once())->method('resolve')->with('example.invalid')->willReturn(reject($exception));
 
         $promise = $this->connector->connect('example.invalid:80');
 
@@ -220,7 +222,7 @@ public function testRejectionExceptionUsesPreviousExceptionIfDnsFails()
     public function testCancelDuringDnsCancelsDnsAndDoesNotStartTcpConnection()
     {
         $pending = new Promise(function () { }, $this->expectCallableOnce());
-        $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('example.com'))->will($this->returnValue($pending));
+        $this->resolver->expects($this->once())->method('resolve')->with('example.com')->willReturn($pending);
         $this->tcp->expects($this->never())->method('connect');
 
         $promise = $this->connector->connect('example.com:80');
@@ -232,7 +234,7 @@ public function testCancelDuringDnsCancelsDnsAndDoesNotStartTcpConnection()
         });
 
         assert($exception instanceof \RuntimeException);
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         $this->assertEquals('Connection to tcp://example.com:80 cancelled during DNS lookup (ECONNABORTED)', $exception->getMessage());
         $this->assertEquals(defined('SOCKET_ECONNABORTED') ? SOCKET_ECONNABORTED : 103, $exception->getCode());
         $this->assertNull($exception->getPrevious());
@@ -243,7 +245,7 @@ public function testCancelDuringTcpConnectionCancelsTcpConnectionIfGivenIp()
     {
         $pending = new Promise(function () { }, $this->expectCallableOnce());
         $this->resolver->expects($this->never())->method('resolve');
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('1.2.3.4:80'))->willReturn($pending);
+        $this->tcp->expects($this->once())->method('connect')->with('1.2.3.4:80')->willReturn($pending);
 
         $promise = $this->connector->connect('1.2.3.4:80');
         $promise->cancel();
@@ -252,8 +254,8 @@ public function testCancelDuringTcpConnectionCancelsTcpConnectionIfGivenIp()
     public function testCancelDuringTcpConnectionCancelsTcpConnectionAfterDnsIsResolved()
     {
         $pending = new Promise(function () { }, $this->expectCallableOnce());
-        $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('example.com'))->willReturn(resolve('1.2.3.4'));
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('1.2.3.4:80?hostname=example.com'))->willReturn($pending);
+        $this->resolver->expects($this->once())->method('resolve')->with('example.com')->willReturn(resolve('1.2.3.4'));
+        $this->tcp->expects($this->once())->method('connect')->with('1.2.3.4:80?hostname=example.com')->willReturn($pending);
 
         $promise = $this->connector->connect('example.com:80');
         $promise->cancel();
@@ -262,14 +264,14 @@ public function testCancelDuringTcpConnectionCancelsTcpConnectionAfterDnsIsResol
     public function testCancelDuringTcpConnectionCancelsTcpConnectionWithTcpRejectionAfterDnsIsResolved()
     {
         $first = new Deferred();
-        $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('example.com'))->willReturn($first->promise());
+        $this->resolver->expects($this->once())->method('resolve')->with('example.com')->willReturn($first->promise());
         $pending = new Promise(function () { }, function () {
             throw new \RuntimeException(
                 'Connection cancelled',
                 defined('SOCKET_ECONNABORTED') ? SOCKET_ECONNABORTED : 103
             );
         });
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('1.2.3.4:80?hostname=example.com'))->willReturn($pending);
+        $this->tcp->expects($this->once())->method('connect')->with('1.2.3.4:80?hostname=example.com')->willReturn($pending);
 
         $promise = $this->connector->connect('example.com:80');
         $first->resolve('1.2.3.4');
@@ -282,10 +284,10 @@ public function testCancelDuringTcpConnectionCancelsTcpConnectionWithTcpRejectio
         });
 
         assert($exception instanceof \RuntimeException);
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         $this->assertEquals('Connection to tcp://example.com:80 failed: Connection cancelled', $exception->getMessage());
         $this->assertEquals(defined('SOCKET_ECONNABORTED') ? SOCKET_ECONNABORTED : 103, $exception->getCode());
-        $this->assertInstanceOf('RuntimeException', $exception->getPrevious());
+        $this->assertInstanceOf(\RuntimeException::class, $exception->getPrevious());
         $this->assertNotEquals('', $exception->getTraceAsString());
     }
 
@@ -300,7 +302,7 @@ public function testRejectionDuringDnsLookupShouldNotCreateAnyGarbageReferences(
         }
 
         $dns = new Deferred();
-        $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('example.com'))->willReturn($dns->promise());
+        $this->resolver->expects($this->once())->method('resolve')->with('example.com')->willReturn($dns->promise());
         $this->tcp->expects($this->never())->method('connect');
 
         $promise = $this->connector->connect('example.com:80');
@@ -324,10 +326,10 @@ public function testRejectionAfterDnsLookupShouldNotCreateAnyGarbageReferences()
         }
 
         $dns = new Deferred();
-        $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('example.com'))->willReturn($dns->promise());
+        $this->resolver->expects($this->once())->method('resolve')->with('example.com')->willReturn($dns->promise());
 
         $tcp = new Deferred();
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('1.2.3.4:80?hostname=example.com'))->willReturn($tcp->promise());
+        $this->tcp->expects($this->once())->method('connect')->with('1.2.3.4:80?hostname=example.com')->willReturn($tcp->promise());
 
         $promise = $this->connector->connect('example.com:80');
 
@@ -351,13 +353,13 @@ public function testRejectionAfterDnsLookupShouldNotCreateAnyGarbageReferencesAg
         }
 
         $dns = new Deferred();
-        $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('example.com'))->willReturn($dns->promise());
+        $this->resolver->expects($this->once())->method('resolve')->with('example.com')->willReturn($dns->promise());
 
         $tcp = new Deferred();
         $dns->promise()->then(function () use ($tcp) {
             $tcp->reject(new \RuntimeException('Connection failed'));
         });
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('1.2.3.4:80?hostname=example.com'))->willReturn($tcp->promise());
+        $this->tcp->expects($this->once())->method('connect')->with('1.2.3.4:80?hostname=example.com')->willReturn($tcp->promise());
 
         $promise = $this->connector->connect('example.com:80');
 
@@ -383,7 +385,7 @@ public function testCancelDuringDnsLookupShouldNotCreateAnyGarbageReferences()
         $dns = new Deferred(function () {
             throw new \RuntimeException();
         });
-        $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('example.com'))->willReturn($dns->promise());
+        $this->resolver->expects($this->once())->method('resolve')->with('example.com')->willReturn($dns->promise());
         $this->tcp->expects($this->never())->method('connect');
 
         $promise = $this->connector->connect('example.com:80');
@@ -405,11 +407,11 @@ public function testCancelDuringTcpConnectionShouldNotCreateAnyGarbageReferences
         }
 
         $dns = new Deferred();
-        $this->resolver->expects($this->once())->method('resolve')->with($this->equalTo('example.com'))->willReturn($dns->promise());
+        $this->resolver->expects($this->once())->method('resolve')->with('example.com')->willReturn($dns->promise());
         $tcp = new Promise(function () { }, function () {
             throw new \RuntimeException('Connection cancelled');
         });
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('1.2.3.4:80?hostname=example.com'))->willReturn($tcp);
+        $this->tcp->expects($this->once())->method('connect')->with('1.2.3.4:80?hostname=example.com')->willReturn($tcp);
 
         $promise = $this->connector->connect('example.com:80');
         $dns->resolve('1.2.3.4');
diff --git a/tests/FdServerTest.php b/tests/FdServerTest.php
index e7d3c67..4ecd81e 100644
--- a/tests/FdServerTest.php
+++ b/tests/FdServerTest.php
@@ -2,6 +2,7 @@
 
 namespace React\Tests\Socket;
 
+use React\EventLoop\LoopInterface;
 use React\Promise\Promise;
 use React\Socket\ConnectionInterface;
 use React\Socket\FdServer;
@@ -20,7 +21,7 @@ public function testCtorAddsResourceToLoop()
         $socket = stream_socket_server('127.0.0.1:0');
         assert($socket !== false);
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addReadStream');
 
         new FdServer($fd, $loop);
@@ -28,27 +29,23 @@ public function testCtorAddsResourceToLoop()
 
     public function testCtorThrowsForInvalidFd()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->never())->method('addReadStream');
 
-        $this->setExpectedException(
-            'InvalidArgumentException',
-            'Invalid FD number given (EINVAL)',
-            defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
-        );
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Invalid FD number given (EINVAL)');
+        $this->expectExceptionCode(defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22));
         new FdServer(-1, $loop);
     }
 
     public function testCtorThrowsForInvalidUrl()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->never())->method('addReadStream');
 
-        $this->setExpectedException(
-            'InvalidArgumentException',
-            'Invalid FD number given (EINVAL)',
-            defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
-        );
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Invalid FD number given (EINVAL)');
+        $this->expectExceptionCode(defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22));
         new FdServer('tcp://127.0.0.1:8080', $loop);
     }
 
@@ -60,7 +57,7 @@ public function testCtorThrowsForUnknownFdWithoutCallingCustomErrorHandler()
 
         $fd = self::getNextFreeFd();
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->never())->method('addReadStream');
 
         $error = null;
@@ -68,11 +65,9 @@ public function testCtorThrowsForUnknownFdWithoutCallingCustomErrorHandler()
             $error = $errstr;
         });
 
-        $this->setExpectedException(
-            'RuntimeException',
-            'Failed to listen on FD ' . $fd . ': ' . (function_exists('socket_strerror') ? socket_strerror(SOCKET_EBADF) . ' (EBADF)' : 'Bad file descriptor'),
-            defined('SOCKET_EBADF') ? SOCKET_EBADF : 9
-        );
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('Failed to listen on FD ' . $fd . ': ' . (function_exists('socket_strerror') ? socket_strerror(SOCKET_EBADF) . ' (EBADF)' : 'Bad file descriptor'));
+        $this->expectExceptionCode(defined('SOCKET_EBADF') ? SOCKET_EBADF : 9);
 
         try {
             new FdServer($fd, $loop);
@@ -96,14 +91,12 @@ public function testCtorThrowsIfFdIsAFileAndNotASocket()
         $tmpfile = tmpfile();
         assert($tmpfile !== false);
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->never())->method('addReadStream');
 
-        $this->setExpectedException(
-            'RuntimeException',
-            'Failed to listen on FD ' . $fd . ': ' . (function_exists('socket_strerror') ? socket_strerror(SOCKET_ENOTSOCK) : 'Not a socket') . ' (ENOTSOCK)',
-            defined('SOCKET_ENOTSOCK') ? SOCKET_ENOTSOCK : 88
-        );
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('Failed to listen on FD ' . $fd . ': ' . (function_exists('socket_strerror') ? socket_strerror(SOCKET_ENOTSOCK) : 'Not a socket') . ' (ENOTSOCK)');
+        $this->expectExceptionCode(defined('SOCKET_ENOTSOCK') ? SOCKET_ENOTSOCK : 88);
         new FdServer($fd, $loop);
     }
 
@@ -119,14 +112,12 @@ public function testCtorThrowsIfFdIsAConnectedSocketInsteadOfServerSocket()
         $client = stream_socket_client('tcp://' . stream_socket_get_name($socket, false));
         assert($client !== false);
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->never())->method('addReadStream');
 
-        $this->setExpectedException(
-            'RuntimeException',
-            'Failed to listen on FD ' . $fd . ': ' . (function_exists('socket_strerror') ? socket_strerror(SOCKET_EISCONN) : 'Socket is connected') . ' (EISCONN)',
-            defined('SOCKET_EISCONN') ? SOCKET_EISCONN : 106
-        );
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('Failed to listen on FD ' . $fd . ': ' . (function_exists('socket_strerror') ? socket_strerror(SOCKET_EISCONN) : 'Socket is connected') . ' (EISCONN)');
+        $this->expectExceptionCode(defined('SOCKET_EISCONN') ? SOCKET_EISCONN : 106);
         new FdServer($fd, $loop);
     }
 
@@ -139,7 +130,7 @@ public function testGetAddressReturnsSameAddressAsOriginalSocketForIpv4Socket()
         $fd = self::getNextFreeFd();
         $socket = stream_socket_server('127.0.0.1:0');
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $server = new FdServer($fd, $loop);
 
@@ -155,7 +146,7 @@ public function testGetAddressReturnsSameAddressAsOriginalSocketForIpv4SocketGiv
         $fd = self::getNextFreeFd();
         $socket = stream_socket_server('127.0.0.1:0');
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $server = new FdServer('php://fd/' . $fd, $loop);
 
@@ -174,7 +165,7 @@ public function testGetAddressReturnsSameAddressAsOriginalSocketForIpv6Socket()
             $this->markTestSkipped('Listening on IPv6 not supported');
         }
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $server = new FdServer($fd, $loop);
 
@@ -197,7 +188,7 @@ public function testGetAddressReturnsSameAddressAsOriginalSocketForUnixDomainSoc
         assert(is_resource($socket));
         unlink(str_replace('unix://', '', stream_socket_get_name($socket, false)));
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $server = new FdServer($fd, $loop);
 
@@ -214,7 +205,7 @@ public function testGetAddressReturnsNullAfterClose()
         $socket = stream_socket_server('127.0.0.1:0');
         assert($socket !== false);
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $server = new FdServer($fd, $loop);
         $server->close();
@@ -232,7 +223,7 @@ public function testCloseRemovesResourceFromLoop()
         $socket = stream_socket_server('127.0.0.1:0');
         assert($socket !== false);
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('removeReadStream');
 
         $server = new FdServer($fd, $loop);
@@ -249,7 +240,7 @@ public function testCloseTwiceRemovesResourceFromLoopOnce()
         $socket = stream_socket_server('127.0.0.1:0');
         assert($socket !== false);
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('removeReadStream');
 
         $server = new FdServer($fd, $loop);
@@ -267,7 +258,7 @@ public function testResumeWithoutPauseIsNoOp()
         $socket = stream_socket_server('127.0.0.1:0');
         assert($socket !== false);
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addReadStream');
 
         $server = new FdServer($fd, $loop);
@@ -284,7 +275,7 @@ public function testPauseRemovesResourceFromLoop()
         $socket = stream_socket_server('127.0.0.1:0');
         assert($socket !== false);
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('removeReadStream');
 
         $server = new FdServer($fd, $loop);
@@ -301,7 +292,7 @@ public function testPauseAfterPauseIsNoOp()
         $socket = stream_socket_server('127.0.0.1:0');
         assert($socket !== false);
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('removeReadStream');
 
         $server = new FdServer($fd, $loop);
@@ -331,7 +322,7 @@ public function testServerEmitsConnectionEventForNewConnection()
         /**
          * @var ConnectionInterface $connection
          */
-        $this->assertInstanceOf('React\Socket\ConnectionInterface', $connection);
+        $this->assertInstanceOf(ConnectionInterface::class, $connection);
 
         fclose($client);
         $connection->close();
@@ -345,7 +336,7 @@ public function testEmitsErrorWhenAcceptListenerFailsWithoutCallingCustomErrorHa
         }
 
         $listener = null;
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addReadStream')->with($this->anything(), $this->callback(function ($cb) use (&$listener) {
             $listener = $cb;
             return true;
@@ -379,7 +370,7 @@ public function testEmitsErrorWhenAcceptListenerFailsWithoutCallingCustomErrorHa
 
         $this->assertLessThan(1, $time);
 
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         assert($exception instanceof \RuntimeException);
         $this->assertStringStartsWith('Unable to accept new connection: ', $exception->getMessage());
 
diff --git a/tests/FixedUriConnectorTest.php b/tests/FixedUriConnectorTest.php
index bdc1d77..b649b61 100644
--- a/tests/FixedUriConnectorTest.php
+++ b/tests/FixedUriConnectorTest.php
@@ -2,13 +2,14 @@
 
 namespace React\Tests\Socket;
 
+use React\Socket\ConnectorInterface;
 use React\Socket\FixedUriConnector;
 
 class FixedUriConnectorTest extends TestCase
 {
     public function testWillInvokeGivenConnector()
     {
-        $base = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $base = $this->createMock(ConnectorInterface::class);
         $base->expects($this->once())->method('connect')->with('test')->willReturn('ret');
 
         $connector = new FixedUriConnector('test', $base);
diff --git a/tests/FunctionalConnectorTest.php b/tests/FunctionalConnectorTest.php
index 117e827..ad1aa99 100644
--- a/tests/FunctionalConnectorTest.php
+++ b/tests/FunctionalConnectorTest.php
@@ -30,7 +30,7 @@ public function connectionToTcpServerShouldSucceedWithLocalhost()
 
         $server->close();
 
-        $this->assertInstanceOf('React\Socket\ConnectionInterface', $connection);
+        $this->assertInstanceOf(ConnectionInterface::class, $connection);
 
         $connection->close();
     }
@@ -149,7 +149,7 @@ public function testCancelPendingTlsConnectionDuringTlsHandshakeShouldCloseTcpCo
             await(timeout($promise, self::TIMEOUT));
             $this->fail();
         } catch (\Exception $e) {
-            $this->assertInstanceOf('RuntimeException', $e);
+            $this->assertInstanceOf(\RuntimeException::class, $e);
             $this->assertEquals('Connection to ' . $uri . ' cancelled during TLS handshake (ECONNABORTED)', $e->getMessage());
         }
     }
diff --git a/tests/FunctionalSecureServerTest.php b/tests/FunctionalSecureServerTest.php
index 4c91fae..b30bbbb 100644
--- a/tests/FunctionalSecureServerTest.php
+++ b/tests/FunctionalSecureServerTest.php
@@ -3,6 +3,7 @@
 namespace React\Tests\Socket;
 
 use React\Promise\Promise;
+use React\Socket\Connection;
 use React\Socket\ConnectionInterface;
 use React\Socket\SecureConnector;
 use React\Socket\ServerInterface;
@@ -32,7 +33,7 @@ public function testClientCanConnectToServer()
         /* @var ConnectionInterface $client */
         $client = await(timeout($promise, self::TIMEOUT));
 
-        $this->assertInstanceOf('React\Socket\ConnectionInterface', $client);
+        $this->assertInstanceOf(ConnectionInterface::class, $client);
         $this->assertEquals($server->getAddress(), $client->getRemoteAddress());
 
         $client->close();
@@ -61,7 +62,7 @@ public function testClientUsesTls13ByDefaultWhenSupportedByOpenSSL()
         /* @var ConnectionInterface $client */
         $client = await(timeout($promise, self::TIMEOUT));
 
-        $this->assertInstanceOf('React\Socket\Connection', $client);
+        $this->assertInstanceOf(Connection::class, $client);
         $this->assertTrue(isset($client->stream));
 
         $meta = stream_get_meta_data($client->stream);
@@ -96,7 +97,7 @@ public function testClientUsesTls12WhenCryptoMethodIsExplicitlyConfiguredByClien
         /* @var ConnectionInterface $client */
         $client = await(timeout($promise, self::TIMEOUT));
 
-        $this->assertInstanceOf('React\Socket\Connection', $client);
+        $this->assertInstanceOf(Connection::class, $client);
         $this->assertTrue(isset($client->stream));
 
         $meta = stream_get_meta_data($client->stream);
@@ -123,7 +124,7 @@ public function testClientUsesTls12WhenCryptoMethodIsExplicitlyConfiguredByServe
         /* @var ConnectionInterface $client */
         $client = await(timeout($promise, self::TIMEOUT));
 
-        $this->assertInstanceOf('React\Socket\Connection', $client);
+        $this->assertInstanceOf(Connection::class, $client);
         $this->assertTrue(isset($client->stream));
 
         $meta = stream_get_meta_data($client->stream);
@@ -161,7 +162,7 @@ public function testClientUsesTls10WhenCryptoMethodIsExplicitlyConfiguredByClien
             $this->markTestSkipped('TLS 1.0 not available on this system (' . $e->getMessage() . ')');
         }
 
-        $this->assertInstanceOf('React\Socket\Connection', $client);
+        $this->assertInstanceOf(Connection::class, $client);
         $this->assertTrue(isset($client->stream));
 
         $meta = stream_get_meta_data($client->stream);
@@ -195,8 +196,8 @@ public function testServerEmitsConnectionForClientConnection()
 
         // both ends of the connection are represented by different instances of ConnectionInterface
         $this->assertCount(2, $both);
-        $this->assertInstanceOf('React\Socket\ConnectionInterface', $both[0]);
-        $this->assertInstanceOf('React\Socket\ConnectionInterface', $both[1]);
+        $this->assertInstanceOf(ConnectionInterface::class, $both[0]);
+        $this->assertInstanceOf(ConnectionInterface::class, $both[1]);
         $this->assertNotSame($both[0], $both[1]);
 
         // server side end has local server address and client end has remote server address
@@ -484,7 +485,8 @@ public function testEmitsErrorForClientWithTlsVersionMismatch()
         ]);
         $promise = $connector->connect($server->getAddress());
 
-        $this->setExpectedException('RuntimeException', 'handshake');
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('handshake');
 
         try {
             await(timeout($promise, self::TIMEOUT));
@@ -515,7 +517,7 @@ public function testServerEmitsConnectionForNewConnectionWithEncryptedCertificat
 
         $connection = await(timeout($peer, self::TIMEOUT));
 
-        $this->assertInstanceOf('React\Socket\ConnectionInterface', $connection);
+        $this->assertInstanceOf(ConnectionInterface::class, $connection);
 
         $server->close();
         $connection->close();
@@ -533,7 +535,8 @@ public function testClientRejectsWithErrorForServerWithInvalidCertificate()
         ]);
         $promise = $connector->connect($server->getAddress());
 
-        $this->setExpectedException('RuntimeException', 'handshake');
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('handshake');
 
         try {
             await(timeout($promise, self::TIMEOUT));
@@ -569,7 +572,8 @@ public function testServerEmitsErrorForClientWithInvalidCertificate()
             // ignore client-side exception
         }
 
-        $this->setExpectedException('RuntimeException', 'handshake');
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('handshake');
 
         try {
             await(timeout($peer, self::TIMEOUT));
@@ -598,7 +602,8 @@ public function testEmitsErrorForServerWithEncryptedCertificateMissingPassphrase
         ]);
         $promise = $connector->connect($server->getAddress());
 
-        $this->setExpectedException('RuntimeException', 'handshake');
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('handshake');
 
         try {
             await(timeout($promise, self::TIMEOUT));
@@ -628,7 +633,8 @@ public function testEmitsErrorForServerWithEncryptedCertificateWithInvalidPassph
         ]);
         $promise = $connector->connect($server->getAddress());
 
-        $this->setExpectedException('RuntimeException', 'handshake');
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('handshake');
 
         try {
             await(timeout($promise, self::TIMEOUT));
@@ -703,7 +709,7 @@ public function testEmitsErrorIfConnectionIsClosedBeforeHandshake()
         $error = await(timeout($errorEvent, self::TIMEOUT));
 
         // Connection from tcp://127.0.0.1:39528 failed during TLS handshake: Connection lost during TLS handshake (ECONNRESET)
-        $this->assertInstanceOf('RuntimeException', $error);
+        $this->assertInstanceOf(\RuntimeException::class, $error);
         $this->assertStringStartsWith('Connection from tcp://', $error->getMessage());
         $this->assertStringEndsWith('failed during TLS handshake: Connection lost during TLS handshake (ECONNRESET)', $error->getMessage());
         $this->assertEquals(defined('SOCKET_ECONNRESET') ? SOCKET_ECONNRESET : 104, $error->getCode());
@@ -731,7 +737,7 @@ public function testEmitsErrorIfConnectionIsClosedWithIncompleteHandshake()
         $error = await(timeout($errorEvent, self::TIMEOUT));
 
         // Connection from tcp://127.0.0.1:39528 failed during TLS handshake: Connection lost during TLS handshake (ECONNRESET)
-        $this->assertInstanceOf('RuntimeException', $error);
+        $this->assertInstanceOf(\RuntimeException::class, $error);
         $this->assertStringStartsWith('Connection from tcp://', $error->getMessage());
         $this->assertStringEndsWith('failed during TLS handshake: Connection lost during TLS handshake (ECONNRESET)', $error->getMessage());
         $this->assertEquals(defined('SOCKET_ECONNRESET') ? SOCKET_ECONNRESET : 104, $error->getCode());
@@ -753,7 +759,7 @@ public function testEmitsNothingIfPlaintextConnectionIsIdle()
         $promise = $connector->connect(str_replace('tls://', '', $server->getAddress()));
 
         $connection = await(timeout($promise, self::TIMEOUT));
-        $this->assertInstanceOf('React\Socket\ConnectionInterface', $connection);
+        $this->assertInstanceOf(ConnectionInterface::class, $connection);
 
         $server->close();
         $promise->then(function (ConnectionInterface $connection) {
@@ -779,7 +785,7 @@ public function testEmitsErrorIfConnectionIsHttpInsteadOfSecureHandshake()
 
         $error = await(timeout($errorEvent, self::TIMEOUT));
 
-        $this->assertInstanceOf('RuntimeException', $error);
+        $this->assertInstanceOf(\RuntimeException::class, $error);
 
         // OpenSSL error messages are version/platform specific
         // Unable to complete TLS handshake: SSL operation failed with code 1. OpenSSL Error messages: error:1408F10B:SSL routines:SSL3_GET_RECORD:http request
@@ -808,7 +814,7 @@ public function testEmitsErrorIfConnectionIsUnknownProtocolInsteadOfSecureHandsh
 
         $error = await(timeout($errorEvent, self::TIMEOUT));
 
-        $this->assertInstanceOf('RuntimeException', $error);
+        $this->assertInstanceOf(\RuntimeException::class, $error);
 
         // OpenSSL error messages are version/platform specific
         // Unable to complete TLS handshake: SSL operation failed with code 1. OpenSSL Error messages: error:1408F10B:SSL routines:SSL3_GET_RECORD:unknown protocol
diff --git a/tests/FunctionalTcpServerTest.php b/tests/FunctionalTcpServerTest.php
index c612e32..3a08b48 100644
--- a/tests/FunctionalTcpServerTest.php
+++ b/tests/FunctionalTcpServerTest.php
@@ -99,7 +99,7 @@ public function testEmitsConnectionWithRemoteIp()
         $peer = await(timeout($peer, self::TIMEOUT));
         await(sleep(0.0));
 
-        $this->assertContainsString('127.0.0.1:', $peer);
+        $this->assertStringContainsString('127.0.0.1:', $peer);
 
         $server->close();
         $promise->then(function (ConnectionInterface $connection) {
@@ -126,7 +126,7 @@ public function testEmitsConnectionWithLocalIp()
         $local = await(timeout($peer, self::TIMEOUT));
         await(sleep(0.0));
 
-        $this->assertContainsString('127.0.0.1:', $local);
+        $this->assertStringContainsString('127.0.0.1:', $local);
         $this->assertEquals($server->getAddress(), $local);
 
         $server->close();
@@ -156,7 +156,7 @@ public function testEmitsConnectionWithLocalIpDespiteListeningOnAll()
         $local = await(timeout($peer, self::TIMEOUT));
         await(sleep(0.0));
 
-        $this->assertContainsString('127.0.0.1:', $local);
+        $this->assertStringContainsString('127.0.0.1:', $local);
 
         $server->close();
         $promise->then(function (ConnectionInterface $connection) {
@@ -182,7 +182,7 @@ public function testEmitsConnectionWithRemoteIpAfterConnectionIsClosedByPeer()
 
         $peer = await(timeout($peer, self::TIMEOUT));
 
-        $this->assertContainsString('127.0.0.1:', $peer);
+        $this->assertStringContainsString('127.0.0.1:', $peer);
 
         $server->close();
     }
@@ -288,7 +288,7 @@ public function testEmitsConnectionWithRemoteIpv6()
         $peer = await(timeout($peer, self::TIMEOUT));
         await(sleep(0.0));
 
-        $this->assertContainsString('[::1]:', $peer);
+        $this->assertStringContainsString('[::1]:', $peer);
 
         $server->close();
         $promise->then(function (ConnectionInterface $connection) {
@@ -318,7 +318,7 @@ public function testEmitsConnectionWithLocalIpv6()
         $local = await(timeout($peer, self::TIMEOUT));
         await(sleep(0.0));
 
-        $this->assertContainsString('[::1]:', $local);
+        $this->assertStringContainsString('[::1]:', $local);
         $this->assertEquals($server->getAddress(), $local);
 
         $server->close();
@@ -389,41 +389,33 @@ public function testEmitsConnectionWithInheritedContextOptions()
 
     public function testFailsToListenOnInvalidUri()
     {
-        $this->setExpectedException(
-            'InvalidArgumentException',
-            'Invalid URI "tcp://///" given (EINVAL)',
-            defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
-        );
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Invalid URI "tcp://///" given (EINVAL)');
+        $this->expectExceptionCode(defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22));
         new TcpServer('///');
     }
 
     public function testFailsToListenOnUriWithoutPort()
     {
-        $this->setExpectedException(
-            'InvalidArgumentException',
-            'Invalid URI "tcp://127.0.0.1" given (EINVAL)',
-            defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
-        );
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Invalid URI "tcp://127.0.0.1" given (EINVAL)');
+        $this->expectExceptionCode(defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22));
         new TcpServer('127.0.0.1');
     }
 
     public function testFailsToListenOnUriWithWrongScheme()
     {
-        $this->setExpectedException(
-            'InvalidArgumentException',
-            'Invalid URI "udp://127.0.0.1:0" given (EINVAL)',
-            defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
-        );
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Invalid URI "udp://127.0.0.1:0" given (EINVAL)');
+        $this->expectExceptionCode(defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22));
         new TcpServer('udp://127.0.0.1:0');
     }
 
     public function testFailsToListenOnUriWIthHostname()
     {
-        $this->setExpectedException(
-            'InvalidArgumentException',
-            'Given URI "tcp://localhost:8080" does not contain a valid host IP (EINVAL)',
-            defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
-        );
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Given URI "tcp://localhost:8080" does not contain a valid host IP (EINVAL)');
+        $this->expectExceptionCode(defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22));
         new TcpServer('localhost:8080');
     }
 }
diff --git a/tests/HappyEyeBallsConnectionBuilderTest.php b/tests/HappyEyeBallsConnectionBuilderTest.php
index b63a623..60b5ead 100644
--- a/tests/HappyEyeBallsConnectionBuilderTest.php
+++ b/tests/HappyEyeBallsConnectionBuilderTest.php
@@ -2,10 +2,15 @@
 
 namespace React\Tests\Socket;
 
-use React\Promise\Promise;
-use React\Socket\HappyEyeBallsConnectionBuilder;
 use React\Dns\Model\Message;
+use React\Dns\Resolver\ResolverInterface;
+use React\EventLoop\LoopInterface;
+use React\EventLoop\TimerInterface;
 use React\Promise\Deferred;
+use React\Promise\Promise;
+use React\Promise\PromiseInterface;
+use React\Socket\ConnectorInterface;
+use React\Socket\HappyEyeBallsConnectionBuilder;
 use function React\Promise\reject;
 use function React\Promise\resolve;
 
@@ -13,13 +18,13 @@ class HappyEyeBallsConnectionBuilderTest extends TestCase
 {
     public function testConnectWillResolveTwiceViaResolver()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->never())->method('addTimer');
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->never())->method('connect');
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -36,13 +41,13 @@ public function testConnectWillResolveTwiceViaResolver()
 
     public function testConnectWillRejectWhenBothDnsLookupsReject()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->never())->method('addTimer');
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->never())->method('connect');
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -63,24 +68,24 @@ public function testConnectWillRejectWhenBothDnsLookupsReject()
             $exception = $e;
         });
 
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         assert($exception instanceof \RuntimeException);
 
         $this->assertEquals('Connection to tcp://reactphp.org:80 failed during DNS lookup: DNS lookup error', $exception->getMessage());
         $this->assertEquals(0, $exception->getCode());
-        $this->assertInstanceOf('RuntimeException', $exception->getPrevious());
+        $this->assertInstanceOf(\RuntimeException::class, $exception->getPrevious());
     }
 
     public function testConnectWillRejectWhenBothDnsLookupsRejectWithDifferentMessages()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->never())->method('addTimer');
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->never())->method('connect');
 
         $deferred = new Deferred();
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -103,24 +108,24 @@ public function testConnectWillRejectWhenBothDnsLookupsRejectWithDifferentMessag
             $exception = $e;
         });
 
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         assert($exception instanceof \RuntimeException);
 
         $this->assertEquals('Connection to tcp://reactphp.org:80 failed during DNS lookup. Last error for IPv6: DNS6 error. Previous error for IPv4: DNS4 error', $exception->getMessage());
         $this->assertEquals(0, $exception->getCode());
-        $this->assertInstanceOf('RuntimeException', $exception->getPrevious());
+        $this->assertInstanceOf(\RuntimeException::class, $exception->getPrevious());
     }
 
     public function testConnectWillStartDelayTimerWhenIpv4ResolvesAndIpv6IsPending()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->with(0.05, $this->anything());
         $loop->expects($this->never())->method('cancelTimer');
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->never())->method('connect');
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -140,14 +145,14 @@ public function testConnectWillStartDelayTimerWhenIpv4ResolvesAndIpv6IsPending()
 
     public function testConnectWillStartConnectingWithAttemptTimerButWithoutResolutionTimerWhenIpv6ResolvesAndIpv4IsPending()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->with(0.1, $this->anything());
         $loop->expects($this->never())->method('cancelTimer');
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('tcp://[::1]:80?hostname=reactphp.org')->willReturn(new Promise(function () { }));
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -168,17 +173,17 @@ public function testConnectWillStartConnectingWithAttemptTimerButWithoutResoluti
     public function testConnectWillStartConnectingAndWillStartNextConnectionWithNewAttemptTimerWhenNextAttemptTimerFiresWithIpv4StillPending()
     {
         $timer = null;
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->exactly(2))->method('addTimer')->with(0.1, $this->callback(function ($cb) use (&$timer) {
             $timer = $cb;
             return true;
         }));
         $loop->expects($this->never())->method('cancelTimer');
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->exactly(2))->method('connect')->willReturn(new Promise(function () { }));
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -202,17 +207,17 @@ public function testConnectWillStartConnectingAndWillStartNextConnectionWithNewA
     public function testConnectWillStartConnectingAndWillDoNothingWhenNextAttemptTimerFiresWithNoOtherIps()
     {
         $timer = null;
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->with(0.1, $this->callback(function ($cb) use (&$timer) {
             $timer = $cb;
             return true;
         }));
         $loop->expects($this->never())->method('cancelTimer');
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('tcp://[::1]:80?hostname=reactphp.org')->willReturn(new Promise(function () { }));
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -235,16 +240,16 @@ public function testConnectWillStartConnectingAndWillDoNothingWhenNextAttemptTim
 
     public function testConnectWillStartConnectingWithAttemptTimerButWithoutResolutionTimerWhenIpv6ResolvesAndWillCancelAttemptTimerWhenIpv4Rejects()
     {
-        $timer = $this->getMockBuilder('React\EventLoop\TimerInterface')->getMock();
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $timer = $this->createMock(TimerInterface::class);
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->with(0.1, $this->anything())->willReturn($timer);
         $loop->expects($this->once())->method('cancelTimer')->with($timer);
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('tcp://[::1]:80?hostname=reactphp.org')->willReturn(new Promise(function () { }));
 
         $deferred = new Deferred();
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -265,13 +270,13 @@ public function testConnectWillStartConnectingWithAttemptTimerButWithoutResoluti
 
     public function testConnectWillStartConnectingWithAttemptTimerWhenIpv6AndIpv4ResolvesAndWillStartNextConnectionAttemptWithoutAttemptTimerImmediatelyWhenFirstConnectionAttemptFails()
     {
-        $timer = $this->getMockBuilder('React\EventLoop\TimerInterface')->getMock();
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $timer = $this->createMock(TimerInterface::class);
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->with(0.1, $this->anything())->willReturn($timer);
         $loop->expects($this->once())->method('cancelTimer')->with($timer);
 
         $deferred = new Deferred();
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->exactly(2))->method('connect')->withConsecutive(
             ['tcp://[::1]:80?hostname=reactphp.org'],
             ['tcp://127.0.0.1:80?hostname=reactphp.org']
@@ -280,7 +285,7 @@ public function testConnectWillStartConnectingWithAttemptTimerWhenIpv6AndIpv4Res
             new Promise(function () { })
         );
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -302,13 +307,13 @@ public function testConnectWillStartConnectingWithAttemptTimerWhenIpv6AndIpv4Res
 
     public function testConnectWillStartConnectingWithAlternatingIPv6AndIPv4WhenResolverReturnsMultipleIPAdresses()
     {
-        $timer = $this->getMockBuilder('React\EventLoop\TimerInterface')->getMock();
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $timer = $this->createMock(TimerInterface::class);
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->with(0.1, $this->anything())->willReturn($timer);
         $loop->expects($this->once())->method('cancelTimer')->with($timer);
 
         $deferred = new Deferred();
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->exactly(4))->method('connect')->withConsecutive(
             ['tcp://[::1]:80?hostname=reactphp.org'],
             ['tcp://127.0.0.1:80?hostname=reactphp.org'],
@@ -321,7 +326,7 @@ public function testConnectWillStartConnectingWithAlternatingIPv6AndIPv4WhenReso
             new Promise(function () { })
         );
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -343,12 +348,12 @@ public function testConnectWillStartConnectingWithAlternatingIPv6AndIPv4WhenReso
 
     public function testConnectWillStartConnectingWithAttemptTimerWhenOnlyIpv6ResolvesAndWillStartNextConnectionAttemptWithoutAttemptTimerImmediatelyWhenFirstConnectionAttemptFails()
     {
-        $timer = $this->getMockBuilder('React\EventLoop\TimerInterface')->getMock();
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $timer = $this->createMock(TimerInterface::class);
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->with(0.1, $this->anything())->willReturn($timer);
         $loop->expects($this->once())->method('cancelTimer')->with($timer);
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->exactly(2))->method('connect')->withConsecutive(
             ['tcp://[::1]:80?hostname=reactphp.org'],
             ['tcp://[::1]:80?hostname=reactphp.org']
@@ -357,7 +362,7 @@ public function testConnectWillStartConnectingWithAttemptTimerWhenOnlyIpv6Resolv
             new Promise(function () { })
         );
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -378,18 +383,18 @@ public function testConnectWillStartConnectingWithAttemptTimerWhenOnlyIpv6Resolv
     public function testConnectWillStartConnectingAndWillStartNextConnectionWithoutNewAttemptTimerWhenNextAttemptTimerFiresAfterIpv4Rejected()
     {
         $timer = null;
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->with(0.1, $this->callback(function ($cb) use (&$timer) {
             $timer = $cb;
             return true;
         }));
         $loop->expects($this->never())->method('cancelTimer');
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->exactly(2))->method('connect')->willReturn(new Promise(function () { }));
 
         $deferred = new Deferred();
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -413,20 +418,20 @@ public function testConnectWillStartConnectingAndWillStartNextConnectionWithoutN
 
     public function testConnectWillStartAndCancelResolutionTimerAndStartAttemptTimerWhenIpv4ResolvesAndIpv6ResolvesAfterwardsAndStartConnectingToIpv6()
     {
-        $timerDelay = $this->getMockBuilder('React\EventLoop\TimerInterface')->getMock();
-        $timerAttempt = $this->getMockBuilder('React\EventLoop\TimerInterface')->getMock();
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $timerDelay = $this->createMock(TimerInterface::class);
+        $timerAttempt = $this->createMock(TimerInterface::class);
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->exactly(2))->method('addTimer')->withConsecutive(
             [0.05, $this->anything()],
             [0.1, $this->anything()]
         )->willReturnOnConsecutiveCalls($timerDelay, $timerAttempt);
         $loop->expects($this->once())->method('cancelTimer')->with($timerDelay);
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('tcp://[::1]:80?hostname=reactphp.org')->willReturn(new Promise(function () { }));
 
         $deferred = new Deferred();
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -447,16 +452,16 @@ public function testConnectWillStartAndCancelResolutionTimerAndStartAttemptTimer
 
     public function testConnectWillRejectWhenOnlyTcp6ConnectionRejectsAndCancelNextAttemptTimerImmediately()
     {
-        $timer = $this->getMockBuilder('React\EventLoop\TimerInterface')->getMock();
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $timer = $this->createMock(TimerInterface::class);
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->with(0.1, $this->anything())->willReturn($timer);
         $loop->expects($this->once())->method('cancelTimer')->with($timer);
 
         $deferred = new Deferred();
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('tcp://[::1]:80?hostname=reactphp.org')->willReturn($deferred->promise());
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -482,24 +487,24 @@ public function testConnectWillRejectWhenOnlyTcp6ConnectionRejectsAndCancelNextA
             $exception = $e;
         });
 
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         assert($exception instanceof \RuntimeException);
 
         $this->assertEquals('Connection to tcp://reactphp.org:80 failed: Last error for IPv6: Connection refused (ECONNREFUSED). Previous error for IPv4: DNS failed', $exception->getMessage());
         $this->assertEquals(defined('SOCKET_ECONNREFUSED') ? SOCKET_ECONNREFUSED : 111, $exception->getCode());
-        $this->assertInstanceOf('RuntimeException', $exception->getPrevious());
+        $this->assertInstanceOf(\RuntimeException::class, $exception->getPrevious());
     }
 
     public function testConnectWillRejectWhenOnlyTcp4ConnectionRejectsAndWillNeverStartNextAttemptTimer()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->never())->method('addTimer');
 
         $deferred = new Deferred();
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('tcp://127.0.0.1:80?hostname=reactphp.org')->willReturn($deferred->promise());
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -525,26 +530,26 @@ public function testConnectWillRejectWhenOnlyTcp4ConnectionRejectsAndWillNeverSt
             $exception = $e;
         });
 
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         assert($exception instanceof \RuntimeException);
 
         $this->assertEquals('Connection to tcp://reactphp.org:80 failed: Last error for IPv4: Connection refused (ECONNREFUSED). Previous error for IPv6: DNS failed', $exception->getMessage());
         $this->assertEquals(defined('SOCKET_ECONNREFUSED') ? SOCKET_ECONNREFUSED : 111, $exception->getCode());
-        $this->assertInstanceOf('RuntimeException', $exception->getPrevious());
+        $this->assertInstanceOf(\RuntimeException::class, $exception->getPrevious());
     }
 
     public function testConnectWillRejectWhenAllConnectionsRejectAndCancelNextAttemptTimerImmediately()
     {
-        $timer = $this->getMockBuilder('React\EventLoop\TimerInterface')->getMock();
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $timer = $this->createMock(TimerInterface::class);
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->with(0.1, $this->anything())->willReturn($timer);
         $loop->expects($this->once())->method('cancelTimer')->with($timer);
 
         $deferred = new Deferred();
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->exactly(2))->method('connect')->willReturn($deferred->promise());
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -570,23 +575,23 @@ public function testConnectWillRejectWhenAllConnectionsRejectAndCancelNextAttemp
             $exception = $e;
         });
 
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         assert($exception instanceof \RuntimeException);
 
         $this->assertEquals('Connection to tcp://reactphp.org:80 failed: Connection refused (ECONNREFUSED)', $exception->getMessage());
         $this->assertEquals(defined('SOCKET_ECONNREFUSED') ? SOCKET_ECONNREFUSED : 111, $exception->getCode());
-        $this->assertInstanceOf('RuntimeException', $exception->getPrevious());
+        $this->assertInstanceOf(\RuntimeException::class, $exception->getPrevious());
     }
 
     public function testConnectWillRejectWithMessageWithoutHostnameWhenAllConnectionsRejectAndCancelNextAttemptTimerImmediately()
     {
-        $timer = $this->getMockBuilder('React\EventLoop\TimerInterface')->getMock();
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $timer = $this->createMock(TimerInterface::class);
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->with(0.1, $this->anything())->willReturn($timer);
         $loop->expects($this->once())->method('cancelTimer')->with($timer);
 
         $deferred = new Deferred();
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->exactly(2))->method('connect')->willReturnOnConsecutiveCalls(
             $deferred->promise(),
             reject(new \RuntimeException(
@@ -595,7 +600,7 @@ public function testConnectWillRejectWithMessageWithoutHostnameWhenAllConnection
             ))
         );
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['localhost', Message::TYPE_AAAA],
             ['localhost', Message::TYPE_A]
@@ -621,24 +626,24 @@ public function testConnectWillRejectWithMessageWithoutHostnameWhenAllConnection
             $exception = $e;
         });
 
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         assert($exception instanceof \RuntimeException);
 
         $this->assertEquals('Connection to tcp://localhost:80 failed: Last error for IPv4: Connection to tcp://127.0.0.1:80 failed: Connection refused (ECONNREFUSED). Previous error for IPv6: Connection to tcp://[::1]:80 failed: Connection refused (ECONNREFUSED)', $exception->getMessage());
         $this->assertEquals(defined('SOCKET_ECONNREFUSED') ? SOCKET_ECONNREFUSED : 111, $exception->getCode());
-        $this->assertInstanceOf('RuntimeException', $exception->getPrevious());
+        $this->assertInstanceOf(\RuntimeException::class, $exception->getPrevious());
     }
 
     public function testCancelConnectWillRejectPromiseAndCancelBothDnsLookups()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->never())->method('addTimer');
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->never())->method('connect');
 
         $cancelled = 0;
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -669,7 +674,7 @@ public function testCancelConnectWillRejectPromiseAndCancelBothDnsLookups()
             $exception = $e;
         });
 
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         assert($exception instanceof \RuntimeException);
 
         $this->assertEquals('Connection to tcp://reactphp.org:80 cancelled during DNS lookup (ECONNABORTED)', $exception->getMessage());
@@ -678,15 +683,15 @@ public function testCancelConnectWillRejectPromiseAndCancelBothDnsLookups()
 
     public function testCancelConnectWillRejectPromiseAndCancelPendingIpv6LookupAndCancelDelayTimer()
     {
-        $timer = $this->getMockBuilder('React\EventLoop\TimerInterface')->getMock();
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $timer = $this->createMock(TimerInterface::class);
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->willReturn($timer);
         $loop->expects($this->once())->method('cancelTimer')->with($timer);
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->never())->method('connect');
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -711,7 +716,7 @@ public function testCancelConnectWillRejectPromiseAndCancelPendingIpv6LookupAndC
             $exception = $e;
         });
 
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         assert($exception instanceof \RuntimeException);
 
         $this->assertEquals('Connection to tcp://reactphp.org:80 cancelled during DNS lookup (ECONNABORTED)', $exception->getMessage());
@@ -720,19 +725,19 @@ public function testCancelConnectWillRejectPromiseAndCancelPendingIpv6LookupAndC
 
     public function testCancelConnectWillRejectPromiseAndCancelPendingIpv6ConnectionAttemptAndPendingIpv4LookupAndCancelAttemptTimer()
     {
-        $timer = $this->getMockBuilder('React\EventLoop\TimerInterface')->getMock();
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $timer = $this->createMock(TimerInterface::class);
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->with(0.1, $this->anything())->willReturn($timer);
         $loop->expects($this->once())->method('cancelTimer')->with($timer);
 
         $cancelled = 0;
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('tcp://[::1]:80?hostname=reactphp.org')->willReturn(new Promise(function () { }, function () use (&$cancelled) {
             ++$cancelled;
             throw new \RuntimeException('Ignored message');
         }));
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->exactly(2))->method('resolveAll')->withConsecutive(
             ['reactphp.org', Message::TYPE_AAAA],
             ['reactphp.org', Message::TYPE_A]
@@ -757,7 +762,7 @@ public function testCancelConnectWillRejectPromiseAndCancelPendingIpv6Connection
             $exception = $e;
         });
 
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         assert($exception instanceof \RuntimeException);
 
         $this->assertEquals('Connection to tcp://reactphp.org:80 cancelled (ECONNABORTED)', $exception->getMessage());
@@ -766,11 +771,11 @@ public function testCancelConnectWillRejectPromiseAndCancelPendingIpv6Connection
 
     public function testResolveWillReturnResolvedPromiseWithEmptyListWhenDnsResolverFails()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->once())->method('resolveAll')->with('reactphp.org', Message::TYPE_A)->willReturn(reject(new \RuntimeException()));
 
         $uri = 'tcp://reactphp.org:80';
@@ -781,18 +786,18 @@ public function testResolveWillReturnResolvedPromiseWithEmptyListWhenDnsResolver
 
         $promise = $builder->resolve(Message::TYPE_A, $this->expectCallableNever());
 
-        $this->assertInstanceof('React\Promise\PromiseInterface', $promise);
+        $this->assertInstanceof(PromiseInterface::class, $promise);
         $promise->then($this->expectCallableOnceWith([]), $this->expectCallableNever());
     }
 
     public function testAttemptConnectionWillConnectViaConnectorToGivenIpWithPortAndHostnameFromUriParts()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('tcp://10.1.1.1:80?hostname=reactphp.org')->willReturn(new Promise(function () { }));
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->never())->method('resolveAll');
 
         $uri = 'tcp://reactphp.org:80';
@@ -806,12 +811,12 @@ public function testAttemptConnectionWillConnectViaConnectorToGivenIpWithPortAnd
 
     public function testAttemptConnectionWillConnectViaConnectorToGivenIpv6WithAllUriParts()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('tcp://[::1]:80/path?test=yes&hostname=reactphp.org#start')->willReturn(new Promise(function () { }));
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->never())->method('resolveAll');
 
         $uri = 'tcp://reactphp.org:80/path?test=yes#start';
@@ -825,12 +830,12 @@ public function testAttemptConnectionWillConnectViaConnectorToGivenIpv6WithAllUr
 
     public function testCheckCallsRejectFunctionImmediateWithoutLeavingDanglingPromiseWhenConnectorRejectsImmediately()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('tcp://[::1]:80/path?test=yes&hostname=reactphp.org#start')->willReturn(reject(new \RuntimeException()));
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->never())->method('resolveAll');
 
         $uri = 'tcp://reactphp.org:80/path?test=yes#start';
@@ -854,15 +859,15 @@ public function testCheckCallsRejectFunctionImmediateWithoutLeavingDanglingPromi
 
     public function testCleanUpCancelsAllPendingConnectionAttempts()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->exactly(2))->method('connect')->with('tcp://[::1]:80/path?test=yes&hostname=reactphp.org#start')->willReturnOnConsecutiveCalls(
             new Promise(function () { }, $this->expectCallableOnce()),
             new Promise(function () { }, $this->expectCallableOnce())
         );
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->never())->method('resolveAll');
 
         $uri = 'tcp://reactphp.org:80/path?test=yes#start';
@@ -883,14 +888,14 @@ public function testCleanUpCancelsAllPendingConnectionAttempts()
 
     public function testCleanUpCancelsAllPendingConnectionAttemptsWithoutStartingNewAttemptsDueToCancellationRejection()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('tcp://[::1]:80/path?test=yes&hostname=reactphp.org#start')->willReturn(new Promise(function () { }, function () {
             throw new \RuntimeException();
         }));
 
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $resolver = $this->createMock(ResolverInterface::class);
         $resolver->expects($this->never())->method('resolveAll');
 
         $uri = 'tcp://reactphp.org:80/path?test=yes#start';
@@ -910,9 +915,9 @@ public function testCleanUpCancelsAllPendingConnectionAttemptsWithoutStartingNew
 
     public function testMixIpsIntoConnectQueueSometimesAssignsInOriginalOrder()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
+        $connector = $this->createMock(ConnectorInterface::class);
+        $resolver = $this->createMock(ResolverInterface::class);
 
         $uri = 'tcp://reactphp.org:80/path?test=yes#start';
         $host = 'reactphp.org';
@@ -936,9 +941,9 @@ public function testMixIpsIntoConnectQueueSometimesAssignsInOriginalOrder()
 
     public function testMixIpsIntoConnectQueueSometimesAssignsInReverseOrder()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
-        $resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
+        $connector = $this->createMock(ConnectorInterface::class);
+        $resolver = $this->createMock(ResolverInterface::class);
 
         $uri = 'tcp://reactphp.org:80/path?test=yes#start';
         $host = 'reactphp.org';
diff --git a/tests/HappyEyeBallsConnectorTest.php b/tests/HappyEyeBallsConnectorTest.php
index 6d744f0..068aefc 100644
--- a/tests/HappyEyeBallsConnectorTest.php
+++ b/tests/HappyEyeBallsConnectorTest.php
@@ -3,9 +3,13 @@
 namespace React\Tests\Socket;
 
 use React\Dns\Model\Message;
+use React\Dns\Resolver\ResolverInterface;
+use React\EventLoop\LoopInterface;
 use React\EventLoop\StreamSelectLoop;
 use React\Promise\Deferred;
 use React\Promise\Promise;
+use React\Socket\ConnectionInterface;
+use React\Socket\ConnectorInterface;
 use React\Socket\HappyEyeBallsConnector;
 use function React\Promise\reject;
 use function React\Promise\resolve;
@@ -24,9 +28,9 @@ class HappyEyeBallsConnectorTest extends TestCase
     public function setUpMocks()
     {
         $this->loop = new TimerSpeedUpEventLoop(new StreamSelectLoop());
-        $this->tcp = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
-        $this->resolver = $this->getMockBuilder('React\Dns\Resolver\ResolverInterface')->disableOriginalConstructor()->getMock();
-        $this->connection = $this->getMockBuilder('React\Socket\ConnectionInterface')->getMock();
+        $this->tcp = $this->createMock(ConnectorInterface::class);
+        $this->resolver = $this->createMock(ResolverInterface::class);
+        $this->connection = $this->createMock(ConnectionInterface::class);
 
         $this->connector = new HappyEyeBallsConnector($this->loop, $this->tcp, $this->resolver);
     }
@@ -39,15 +43,15 @@ public function testConstructWithoutLoopAssignsLoopAutomatically()
         $ref->setAccessible(true);
         $loop = $ref->getValue($connector);
 
-        $this->assertInstanceOf('React\EventLoop\LoopInterface', $loop);
+        $this->assertInstanceOf(LoopInterface::class, $loop);
     }
 
     public function testHappyFlow()
     {
         $first = new Deferred();
-        $this->resolver->expects($this->exactly(2))->method('resolveAll')->with($this->equalTo('example.com'), $this->anything())->willReturn($first->promise());
-        $connection = $this->getMockBuilder('React\Socket\ConnectionInterface')->getMock();
-        $this->tcp->expects($this->exactly(1))->method('connect')->with($this->equalTo('1.2.3.4:80?hostname=example.com'))->willReturn(resolve($connection));
+        $this->resolver->expects($this->exactly(2))->method('resolveAll')->with('example.com', $this->anything())->willReturn($first->promise());
+        $connection = $this->createMock(ConnectionInterface::class);
+        $this->tcp->expects($this->exactly(1))->method('connect')->with('1.2.3.4:80?hostname=example.com')->willReturn(resolve($connection));
 
         $promise = $this->connector->connect('example.com:80');
         $first->resolve(['1.2.3.4']);
@@ -62,7 +66,7 @@ public function testHappyFlow()
 
     public function testThatAnyOtherPendingConnectionAttemptsWillBeCanceledOnceAConnectionHasBeenEstablished()
     {
-        $connection = $this->getMockBuilder('React\Socket\ConnectionInterface')->getMock();
+        $connection = $this->createMock(ConnectionInterface::class);
         $lookupAttempts = [
             reject(new \Exception('error')),
             resolve(['1.2.3.4', '5.6.7.8', '9.10.11.12']),
@@ -72,12 +76,12 @@ public function testThatAnyOtherPendingConnectionAttemptsWillBeCanceledOnceAConn
             resolve($connection),
             new Promise(function () {}, $this->expectCallableNever()),
         ];
-        $this->resolver->expects($this->exactly(2))->method('resolveAll')->with($this->equalTo('example.com'), $this->anything())->will($this->returnCallback(function () use (&$lookupAttempts) {
+        $this->resolver->expects($this->exactly(2))->method('resolveAll')->with('example.com', $this->anything())->willReturnCallback(function () use (&$lookupAttempts) {
             return array_shift($lookupAttempts);
-        }));
-        $this->tcp->expects($this->exactly(2))->method('connect')->with($this->isType('string'))->will($this->returnCallback(function () use (&$connectionAttempts) {
+        });
+        $this->tcp->expects($this->exactly(2))->method('connect')->with($this->isType('string'))->willReturnCallback(function () use (&$connectionAttempts) {
             return array_shift($connectionAttempts);
-        }));
+        });
 
         $promise = $this->connector->connect('example.com:80');
 
@@ -93,7 +97,7 @@ public function testThatAnyOtherPendingConnectionAttemptsWillBeCanceledOnceAConn
     public function testPassByResolverIfGivenIp()
     {
         $this->resolver->expects($this->never())->method('resolveAll');
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('127.0.0.1:80'))->will($this->returnValue(resolve(null)));
+        $this->tcp->expects($this->once())->method('connect')->with('127.0.0.1:80')->willReturn(resolve(null));
 
         $this->connector->connect('127.0.0.1:80');
 
@@ -103,7 +107,7 @@ public function testPassByResolverIfGivenIp()
     public function testPassByResolverIfGivenIpv6()
     {
         $this->resolver->expects($this->never())->method('resolveAll');
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('[::1]:80'))->will($this->returnValue(reject(new \Exception('reject'))));
+        $this->tcp->expects($this->once())->method('connect')->with('[::1]:80')->willReturn(reject(new \Exception('reject')));
 
         $promise = $this->connector->connect('[::1]:80');
 
@@ -114,8 +118,8 @@ public function testPassByResolverIfGivenIpv6()
 
     public function testPassThroughResolverIfGivenHost()
     {
-        $this->resolver->expects($this->exactly(2))->method('resolveAll')->with($this->equalTo('google.com'), $this->anything())->will($this->returnValue(resolve(['1.2.3.4'])));
-        $this->tcp->expects($this->exactly(2))->method('connect')->with($this->equalTo('1.2.3.4:80?hostname=google.com'))->will($this->returnValue(reject(new \Exception('reject'))));
+        $this->resolver->expects($this->exactly(2))->method('resolveAll')->with('google.com', $this->anything())->willReturn(resolve(['1.2.3.4']));
+        $this->tcp->expects($this->exactly(2))->method('connect')->with('1.2.3.4:80?hostname=google.com')->willReturn(reject(new \Exception('reject')));
 
         $promise = $this->connector->connect('google.com:80');
 
@@ -126,8 +130,8 @@ public function testPassThroughResolverIfGivenHost()
 
     public function testPassThroughResolverIfGivenHostWhichResolvesToIpv6()
     {
-        $this->resolver->expects($this->exactly(2))->method('resolveAll')->with($this->equalTo('google.com'), $this->anything())->will($this->returnValue(resolve(['::1'])));
-        $this->tcp->expects($this->exactly(2))->method('connect')->with($this->equalTo('[::1]:80?hostname=google.com'))->will($this->returnValue(reject(new \Exception('reject'))));
+        $this->resolver->expects($this->exactly(2))->method('resolveAll')->with('google.com', $this->anything())->willReturn(resolve(['::1']));
+        $this->tcp->expects($this->exactly(2))->method('connect')->with('[::1]:80?hostname=google.com')->willReturn(reject(new \Exception('reject')));
 
         $promise = $this->connector->connect('google.com:80');
 
@@ -139,7 +143,7 @@ public function testPassThroughResolverIfGivenHostWhichResolvesToIpv6()
     public function testPassByResolverIfGivenCompleteUri()
     {
         $this->resolver->expects($this->never())->method('resolveAll');
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('scheme://127.0.0.1:80/path?query#fragment'))->will($this->returnValue(reject(new \Exception('reject'))));
+        $this->tcp->expects($this->once())->method('connect')->with('scheme://127.0.0.1:80/path?query#fragment')->willReturn(reject(new \Exception('reject')));
 
         $promise = $this->connector->connect('scheme://127.0.0.1:80/path?query#fragment');
 
@@ -150,8 +154,8 @@ public function testPassByResolverIfGivenCompleteUri()
 
     public function testPassThroughResolverIfGivenCompleteUri()
     {
-        $this->resolver->expects($this->exactly(2))->method('resolveAll')->with($this->equalTo('google.com'), $this->anything())->will($this->returnValue(resolve(['1.2.3.4'])));
-        $this->tcp->expects($this->exactly(2))->method('connect')->with($this->equalTo('scheme://1.2.3.4:80/path?query&hostname=google.com#fragment'))->will($this->returnValue(reject(new \Exception('reject'))));
+        $this->resolver->expects($this->exactly(2))->method('resolveAll')->with('google.com', $this->anything())->willReturn(resolve(['1.2.3.4']));
+        $this->tcp->expects($this->exactly(2))->method('connect')->with('scheme://1.2.3.4:80/path?query&hostname=google.com#fragment')->willReturn(reject(new \Exception('reject')));
 
         $promise = $this->connector->connect('scheme://google.com:80/path?query#fragment');
 
@@ -162,8 +166,8 @@ public function testPassThroughResolverIfGivenCompleteUri()
 
     public function testPassThroughResolverIfGivenExplicitHost()
     {
-        $this->resolver->expects($this->exactly(2))->method('resolveAll')->with($this->equalTo('google.com'), $this->anything())->will($this->returnValue(resolve(['1.2.3.4'])));
-        $this->tcp->expects($this->exactly(2))->method('connect')->with($this->equalTo('scheme://1.2.3.4:80/?hostname=google.de'))->will($this->returnValue(reject(new \Exception('reject'))));
+        $this->resolver->expects($this->exactly(2))->method('resolveAll')->with('google.com', $this->anything())->willReturn(resolve(['1.2.3.4']));
+        $this->tcp->expects($this->exactly(2))->method('connect')->with('scheme://1.2.3.4:80/?hostname=google.de')->willReturn(reject(new \Exception('reject')));
 
         $promise = $this->connector->connect('scheme://google.com:80/?hostname=google.de');
 
@@ -186,7 +190,7 @@ public function testIpv6ResolvesFirstSoIsTheFirstToConnect(array $ipv6, array $i
             $this->returnValue(resolve($ipv6)),
             $this->returnValue($deferred->promise())
         );
-        $this->tcp->expects($this->any())->method('connect')->with($this->stringContains(']:80/?hostname=google.com'))->will($this->returnValue(reject(new \Exception('reject'))));
+        $this->tcp->expects($this->any())->method('connect')->with($this->stringContains(']:80/?hostname=google.com'))->willReturn(reject(new \Exception('reject')));
 
         $this->connector->connect('scheme://google.com:80/?hostname=google.com');
 
@@ -211,7 +215,7 @@ public function testIpv6DoesntResolvesWhileIpv4DoesFirstSoIpv4Connects(array $ip
             $this->returnValue($deferred->promise()),
             $this->returnValue(resolve($ipv4))
         );
-        $this->tcp->expects($this->any())->method('connect')->with($this->stringContains(':80/?hostname=google.com'))->will($this->returnValue(reject(new \Exception('reject'))));
+        $this->tcp->expects($this->any())->method('connect')->with($this->stringContains(':80/?hostname=google.com'))->willReturn(reject(new \Exception('reject')));
 
         $this->connector->connect('scheme://google.com:80/?hostname=google.com');
 
@@ -230,7 +234,7 @@ public function testRejectsImmediatelyIfUriIsInvalid()
         $promise = $this->connector->connect('////');
 
         $promise->then(null, $this->expectCallableOnceWithException(
-            'InvalidArgumentException',
+            \InvalidArgumentException::class,
             'Given URI "////" is invalid (EINVAL)',
             defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
         ));
@@ -240,7 +244,7 @@ public function testRejectsWithTcpConnectorRejectionIfGivenIp()
     {
         $promise = reject(new \RuntimeException('Connection failed'));
         $this->resolver->expects($this->never())->method('resolveAll');
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('1.2.3.4:80'))->willReturn($promise);
+        $this->tcp->expects($this->once())->method('connect')->with('1.2.3.4:80')->willReturn($promise);
 
         $promise = $this->connector->connect('1.2.3.4:80');
         $this->loop->addTimer(0.5, function () use ($promise) {
@@ -249,13 +253,14 @@ public function testRejectsWithTcpConnectorRejectionIfGivenIp()
             $this->throwRejection($promise);
         });
 
-        $this->setExpectedException('RuntimeException', 'Connection failed');
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('Connection failed');
         $this->loop->run();
     }
 
     public function testSkipConnectionIfDnsFails()
     {
-        $this->resolver->expects($this->exactly(2))->method('resolveAll')->with($this->equalTo('example.invalid'), $this->anything())->willReturn(reject(new \RuntimeException('DNS error')));
+        $this->resolver->expects($this->exactly(2))->method('resolveAll')->with('example.invalid', $this->anything())->willReturn(reject(new \RuntimeException('DNS error')));
         $this->tcp->expects($this->never())->method('connect');
 
         $promise = $this->connector->connect('example.invalid:80');
@@ -264,15 +269,16 @@ public function testSkipConnectionIfDnsFails()
             $this->throwRejection($promise);
         });
 
-        $this->setExpectedException('RuntimeException', 'Connection to tcp://example.invalid:80 failed during DNS lookup: DNS error');
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('Connection to tcp://example.invalid:80 failed during DNS lookup: DNS error');
         $this->loop->run();
     }
 
     public function testCancelDuringDnsCancelsDnsAndDoesNotStartTcpConnection()
     {
-        $this->resolver->expects($this->exactly(2))->method('resolveAll')->with('example.com', $this->anything())->will($this->returnCallback(function () {
+        $this->resolver->expects($this->exactly(2))->method('resolveAll')->with('example.com', $this->anything())->willReturnCallback(function () {
             return new Promise(function () { }, $this->expectCallableExactly(1));
-        }));
+        });
         $this->tcp->expects($this->never())->method('connect');
 
         $promise = $this->connector->connect('example.com:80');
@@ -282,11 +288,9 @@ public function testCancelDuringDnsCancelsDnsAndDoesNotStartTcpConnection()
             $this->throwRejection($promise);
         });
 
-        $this->setExpectedException(
-            'RuntimeException',
-            'Connection to tcp://example.com:80 cancelled during DNS lookup (ECONNABORTED)',
-            \defined('SOCKET_ECONNABORTED') ? \SOCKET_ECONNABORTED : 103
-        );
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('Connection to tcp://example.com:80 cancelled during DNS lookup (ECONNABORTED)');
+        $this->expectExceptionCode(\defined('SOCKET_ECONNABORTED') ? \SOCKET_ECONNABORTED : 103);
         $this->loop->run();
     }
 
@@ -294,7 +298,7 @@ public function testCancelDuringTcpConnectionCancelsTcpConnectionIfGivenIp()
     {
         $pending = new Promise(function () { }, $this->expectCallableOnce());
         $this->resolver->expects($this->never())->method('resolveAll');
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('1.2.3.4:80'))->willReturn($pending);
+        $this->tcp->expects($this->once())->method('connect')->with('1.2.3.4:80')->willReturn($pending);
 
         $promise = $this->connector->connect('1.2.3.4:80');
         $this->loop->addTimer(0.1, function () use ($promise) {
@@ -317,7 +321,7 @@ public function throwRejection($promise)
         throw $ex;
     }
 
-    public function provideIpvAddresses()
+    public static function provideIpvAddresses()
     {
         $ipv6 = [
             ['1:2:3:4'],
@@ -330,17 +334,13 @@ public function provideIpvAddresses()
             ['1.2.3.4', '5.6.7.8', '9.10.11.12']
         ];
 
-        $ips = [];
-
         foreach ($ipv6 as $v6) {
             foreach ($ipv4 as $v4) {
-                $ips[] = [
+                yield [
                     $v6,
                     $v4
                 ];
             }
         }
-
-        return $ips;
     }
 }
diff --git a/tests/IntegrationTest.php b/tests/IntegrationTest.php
index acf42c1..361443e 100644
--- a/tests/IntegrationTest.php
+++ b/tests/IntegrationTest.php
@@ -26,7 +26,7 @@ public function gettingStuffFromGoogleShouldWork()
         $conn = await($connector->connect('google.com:80'));
         assert($conn instanceof ConnectionInterface);
 
-        $this->assertContainsString(':80', $conn->getRemoteAddress());
+        $this->assertStringContainsString(':80', $conn->getRemoteAddress());
         $this->assertNotEquals('google.com:80', $conn->getRemoteAddress());
 
         $conn->write("GET / HTTP/1.0\r\n\r\n");
@@ -34,7 +34,7 @@ public function gettingStuffFromGoogleShouldWork()
         $response = $this->buffer($conn, self::TIMEOUT);
         assert(!$conn->isReadable());
 
-        $this->assertMatchesRegExp('#^HTTP/1\.0#', $response);
+        $this->assertStringMatchesFormat('HTTP/1.0%a', $response);
     }
 
     /** @test */
@@ -50,7 +50,7 @@ public function gettingEncryptedStuffFromGoogleShouldWork()
         $response = $this->buffer($conn, self::TIMEOUT);
         assert(!$conn->isReadable());
 
-        $this->assertMatchesRegExp('#^HTTP/1\.0#', $response);
+        $this->assertStringMatchesFormat('HTTP/1.0%a', $response);
     }
 
     /** @test */
@@ -74,7 +74,7 @@ public function gettingEncryptedStuffFromGoogleShouldWorkIfHostIsResolvedFirst()
         $response = $this->buffer($conn, self::TIMEOUT);
         assert(!$conn->isReadable());
 
-        $this->assertMatchesRegExp('#^HTTP/1\.0#', $response);
+        $this->assertStringMatchesFormat('HTTP/1.0%a', $response);
     }
 
     /** @test */
@@ -85,7 +85,7 @@ public function gettingPlaintextStuffFromEncryptedGoogleShouldNotWork()
         $conn = await($connector->connect('google.com:443'));
         assert($conn instanceof ConnectionInterface);
 
-        $this->assertContainsString(':443', $conn->getRemoteAddress());
+        $this->assertStringContainsString(':443', $conn->getRemoteAddress());
         $this->assertNotEquals('google.com:443', $conn->getRemoteAddress());
 
         $conn->write("GET / HTTP/1.0\r\n\r\n");
@@ -93,7 +93,7 @@ public function gettingPlaintextStuffFromEncryptedGoogleShouldNotWork()
         $response = $this->buffer($conn, self::TIMEOUT);
         assert(!$conn->isReadable());
 
-        $this->assertDoesNotMatchRegExp('#^HTTP/1\.0#', $response);
+        $this->assertStringNotMatchesFormat('HTTP/1.0%a', $response);
     }
 
     public function testConnectingFailsIfConnectorUsesInvalidDnsResolverAddress()
@@ -109,7 +109,7 @@ public function testConnectingFailsIfConnectorUsesInvalidDnsResolverAddress()
             'dns' => $dns
         ]);
 
-        $this->setExpectedException('RuntimeException');
+        $this->expectException(\RuntimeException::class);
         await(timeout($connector->connect('google.com:80'), self::TIMEOUT));
     }
 
@@ -365,7 +365,7 @@ public function testConnectingFailsIfTimeoutIsTooSmall()
             'timeout' => 0.001
         ]);
 
-        $this->setExpectedException('RuntimeException');
+        $this->expectException(\RuntimeException::class);
         await(timeout($connector->connect('google.com:80'), self::TIMEOUT));
     }
 
@@ -377,7 +377,7 @@ public function testSelfSignedRejectsIfVerificationIsEnabled()
             ]
         ]);
 
-        $this->setExpectedException('RuntimeException');
+        $this->expectException(\RuntimeException::class);
         await(timeout($connector->connect('tls://self-signed.badssl.com:443'), self::TIMEOUT));
     }
 
diff --git a/tests/LimitingServerTest.php b/tests/LimitingServerTest.php
index 9fc634d..96d4198 100644
--- a/tests/LimitingServerTest.php
+++ b/tests/LimitingServerTest.php
@@ -2,9 +2,11 @@
 
 namespace React\Tests\Socket;
 
+use React\EventLoop\LoopInterface;
 use React\Promise\Promise;
 use React\Socket\ConnectionInterface;
 use React\Socket\LimitingServer;
+use React\Socket\ServerInterface;
 use React\Socket\TcpServer;
 use function React\Async\await;
 use function React\Promise\Timer\timeout;
@@ -15,7 +17,7 @@ class LimitingServerTest extends TestCase
 
     public function testGetAddressWillBePassedThroughToTcpServer()
     {
-        $tcp = $this->getMockBuilder('React\Socket\ServerInterface')->getMock();
+        $tcp = $this->createMock(ServerInterface::class);
         $tcp->expects($this->once())->method('getAddress')->willReturn('127.0.0.1:1234');
 
         $server = new LimitingServer($tcp, 100);
@@ -25,7 +27,7 @@ public function testGetAddressWillBePassedThroughToTcpServer()
 
     public function testPauseWillBePassedThroughToTcpServer()
     {
-        $tcp = $this->getMockBuilder('React\Socket\ServerInterface')->getMock();
+        $tcp = $this->createMock(ServerInterface::class);
         $tcp->expects($this->once())->method('pause');
 
         $server = new LimitingServer($tcp, 100);
@@ -35,7 +37,7 @@ public function testPauseWillBePassedThroughToTcpServer()
 
     public function testPauseTwiceWillBePassedThroughToTcpServerOnce()
     {
-        $tcp = $this->getMockBuilder('React\Socket\ServerInterface')->getMock();
+        $tcp = $this->createMock(ServerInterface::class);
         $tcp->expects($this->once())->method('pause');
 
         $server = new LimitingServer($tcp, 100);
@@ -46,7 +48,7 @@ public function testPauseTwiceWillBePassedThroughToTcpServerOnce()
 
     public function testResumeWillBePassedThroughToTcpServer()
     {
-        $tcp = $this->getMockBuilder('React\Socket\ServerInterface')->getMock();
+        $tcp = $this->createMock(ServerInterface::class);
         $tcp->expects($this->once())->method('resume');
 
         $server = new LimitingServer($tcp, 100);
@@ -57,7 +59,7 @@ public function testResumeWillBePassedThroughToTcpServer()
 
     public function testResumeTwiceWillBePassedThroughToTcpServerOnce()
     {
-        $tcp = $this->getMockBuilder('React\Socket\ServerInterface')->getMock();
+        $tcp = $this->createMock(ServerInterface::class);
         $tcp->expects($this->once())->method('resume');
 
         $server = new LimitingServer($tcp, 100);
@@ -69,7 +71,7 @@ public function testResumeTwiceWillBePassedThroughToTcpServerOnce()
 
     public function testCloseWillBePassedThroughToTcpServer()
     {
-        $tcp = $this->getMockBuilder('React\Socket\ServerInterface')->getMock();
+        $tcp = $this->createMock(ServerInterface::class);
         $tcp->expects($this->once())->method('close');
 
         $server = new LimitingServer($tcp, 100);
@@ -79,7 +81,7 @@ public function testCloseWillBePassedThroughToTcpServer()
 
     public function testSocketErrorWillBeForwarded()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $tcp = new TcpServer(0, $loop);
 
@@ -92,9 +94,9 @@ public function testSocketErrorWillBeForwarded()
 
     public function testSocketConnectionWillBeForwarded()
     {
-        $connection = $this->getMockBuilder('React\Socket\ConnectionInterface')->getMock();
+        $connection = $this->createMock(ConnectionInterface::class);
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $tcp = new TcpServer(0, $loop);
 
@@ -109,12 +111,12 @@ public function testSocketConnectionWillBeForwarded()
 
     public function testSocketConnectionWillBeClosedOnceLimitIsReached()
     {
-        $first = $this->getMockBuilder('React\Socket\ConnectionInterface')->getMock();
+        $first = $this->createMock(ConnectionInterface::class);
         $first->expects($this->never())->method('close');
-        $second = $this->getMockBuilder('React\Socket\ConnectionInterface')->getMock();
+        $second = $this->createMock(ConnectionInterface::class);
         $second->expects($this->once())->method('close');
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $tcp = new TcpServer(0, $loop);
 
@@ -128,13 +130,13 @@ public function testSocketConnectionWillBeClosedOnceLimitIsReached()
 
     public function testPausingServerWillBePausedOnceLimitIsReached()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addReadStream');
         $loop->expects($this->once())->method('removeReadStream');
 
         $tcp = new TcpServer(0, $loop);
 
-        $connection = $this->getMockBuilder('React\Socket\ConnectionInterface')->getMock();
+        $connection = $this->createMock(ConnectionInterface::class);
 
         $server = new LimitingServer($tcp, 1, true);
 
diff --git a/tests/SecureConnectorTest.php b/tests/SecureConnectorTest.php
index 833e874..b96d3c3 100644
--- a/tests/SecureConnectorTest.php
+++ b/tests/SecureConnectorTest.php
@@ -2,9 +2,15 @@
 
 namespace React\Tests\Socket;
 
+use React\EventLoop\LoopInterface;
 use React\Promise\Deferred;
 use React\Promise\Promise;
+use React\Promise\PromiseInterface;
+use React\Socket\Connection;
+use React\Socket\ConnectionInterface;
+use React\Socket\ConnectorInterface;
 use React\Socket\SecureConnector;
+use React\Socket\StreamEncryption;
 use function React\Promise\reject;
 use function React\Promise\resolve;
 
@@ -19,8 +25,8 @@ class SecureConnectorTest extends TestCase
      */
     public function setUpConnector()
     {
-        $this->loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
-        $this->tcp = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $this->loop = $this->createMock(LoopInterface::class);
+        $this->tcp = $this->createMock(ConnectorInterface::class);
         $this->connector = new SecureConnector($this->tcp, $this->loop);
     }
 
@@ -36,23 +42,23 @@ public function testConstructWithoutLoopAssignsLoopAutomatically()
         $ref->setAccessible(true);
         $loop = $ref->getValue($streamEncryption);
 
-        $this->assertInstanceOf('React\EventLoop\LoopInterface', $loop);
+        $this->assertInstanceOf(LoopInterface::class, $loop);
     }
 
     public function testConnectionWillWaitForTcpConnection()
     {
         $pending = new Promise(function () { });
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('example.com:80'))->will($this->returnValue($pending));
+        $this->tcp->expects($this->once())->method('connect')->with('example.com:80')->willReturn($pending);
 
         $promise = $this->connector->connect('example.com:80');
 
-        $this->assertInstanceOf('React\Promise\PromiseInterface', $promise);
+        $this->assertInstanceOf(PromiseInterface::class, $promise);
     }
 
     public function testConnectionWithCompleteUriWillBePassedThroughExpectForScheme()
     {
         $pending = new Promise(function () { });
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('example.com:80/path?query#fragment'))->will($this->returnValue($pending));
+        $this->tcp->expects($this->once())->method('connect')->with('example.com:80/path?query#fragment')->willReturn($pending);
 
         $this->connector->connect('tls://example.com:80/path?query#fragment');
     }
@@ -64,7 +70,7 @@ public function testConnectionToInvalidSchemeWillReject()
         $promise = $this->connector->connect('tcp://example.com:80');
 
         $promise->then(null, $this->expectCallableOnceWithException(
-            'InvalidArgumentException',
+            \InvalidArgumentException::class,
             'Given URI "tcp://example.com:80" is invalid (EINVAL)',
             defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
         ));
@@ -85,10 +91,10 @@ public function testConnectWillRejectWithTlsUriWhenUnderlyingConnectorRejects()
         });
 
         assert($exception instanceof \RuntimeException);
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         $this->assertEquals('Connection to tls://example.com:80 failed: Connection refused (ECONNREFUSED)', $exception->getMessage());
         $this->assertEquals(defined('SOCKET_ECONNREFUSED') ? SOCKET_ECONNREFUSED : 111, $exception->getCode());
-        $this->assertInstanceOf('RuntimeException', $exception->getPrevious());
+        $this->assertInstanceOf(\RuntimeException::class, $exception->getPrevious());
         $this->assertNotEquals('', $exception->getTraceAsString());
     }
 
@@ -107,7 +113,7 @@ public function testConnectWillRejectWithOriginalMessageWhenUnderlyingConnectorR
         });
 
         assert($exception instanceof \InvalidArgumentException);
-        $this->assertInstanceOf('InvalidArgumentException', $exception);
+        $this->assertInstanceOf(\InvalidArgumentException::class, $exception);
         $this->assertEquals('Invalid', $exception->getMessage());
         $this->assertEquals(42, $exception->getCode());
         $this->assertNull($exception->getPrevious());
@@ -129,7 +135,7 @@ public function testCancelDuringTcpConnectionCancelsTcpConnectionAndRejectsWithT
             'Connection to tcp://example.com:80 cancelled (ECONNABORTED)',
             defined('SOCKET_ECONNABORTED') ? SOCKET_ECONNABORTED : 103
         ); });
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('example.com:80'))->will($this->returnValue($pending));
+        $this->tcp->expects($this->once())->method('connect')->with('example.com:80')->willReturn($pending);
 
         $promise = $this->connector->connect('example.com:80');
         $promise->cancel();
@@ -140,19 +146,19 @@ public function testCancelDuringTcpConnectionCancelsTcpConnectionAndRejectsWithT
         });
 
         assert($exception instanceof \RuntimeException);
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         $this->assertEquals('Connection to tls://example.com:80 cancelled (ECONNABORTED)', $exception->getMessage());
         $this->assertEquals(defined('SOCKET_ECONNABORTED') ? SOCKET_ECONNABORTED : 103, $exception->getCode());
-        $this->assertInstanceOf('RuntimeException', $exception->getPrevious());
+        $this->assertInstanceOf(\RuntimeException::class, $exception->getPrevious());
         $this->assertNotEquals('', $exception->getTraceAsString());
     }
 
     public function testConnectionWillBeClosedAndRejectedIfConnectionIsNoStream()
     {
-        $connection = $this->getMockBuilder('React\Socket\ConnectionInterface')->getMock();
+        $connection = $this->createMock(ConnectionInterface::class);
         $connection->expects($this->once())->method('close');
 
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('example.com:80'))->willReturn(resolve($connection));
+        $this->tcp->expects($this->once())->method('connect')->with('example.com:80')->willReturn(resolve($connection));
 
         $promise = $this->connector->connect('example.com:80');
 
@@ -162,7 +168,7 @@ public function testConnectionWillBeClosedAndRejectedIfConnectionIsNoStream()
         });
 
         assert($exception instanceof \UnexpectedValueException);
-        $this->assertInstanceOf('UnexpectedValueException', $exception);
+        $this->assertInstanceOf(\UnexpectedValueException::class, $exception);
         $this->assertEquals('Base connector does not use internal Connection class exposing stream resource', $exception->getMessage());
         $this->assertEquals(0, $exception->getCode());
         $this->assertNull($exception->getPrevious());
@@ -171,33 +177,33 @@ public function testConnectionWillBeClosedAndRejectedIfConnectionIsNoStream()
 
     public function testStreamEncryptionWillBeEnabledAfterConnecting()
     {
-        $connection = $this->getMockBuilder('React\Socket\Connection')->disableOriginalConstructor()->getMock();
+        $connection = $this->createMock(Connection::class);
 
-        $encryption = $this->getMockBuilder('React\Socket\StreamEncryption')->disableOriginalConstructor()->getMock();
+        $encryption = $this->createMock(StreamEncryption::class);
         $encryption->expects($this->once())->method('enable')->with($connection)->willReturn(new Promise(function () { }));
 
         $ref = new \ReflectionProperty($this->connector, 'streamEncryption');
         $ref->setAccessible(true);
         $ref->setValue($this->connector, $encryption);
 
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('example.com:80'))->willReturn(resolve($connection));
+        $this->tcp->expects($this->once())->method('connect')->with('example.com:80')->willReturn(resolve($connection));
 
         $this->connector->connect('example.com:80');
     }
 
     public function testConnectionWillBeRejectedIfStreamEncryptionFailsAndClosesConnection()
     {
-        $connection = $this->getMockBuilder('React\Socket\Connection')->disableOriginalConstructor()->getMock();
+        $connection = $this->createMock(Connection::class);
         $connection->expects($this->once())->method('close');
 
-        $encryption = $this->getMockBuilder('React\Socket\StreamEncryption')->disableOriginalConstructor()->getMock();
+        $encryption = $this->createMock(StreamEncryption::class);
         $encryption->expects($this->once())->method('enable')->willReturn(reject(new \RuntimeException('TLS error', 123)));
 
         $ref = new \ReflectionProperty($this->connector, 'streamEncryption');
         $ref->setAccessible(true);
         $ref->setValue($this->connector, $encryption);
 
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('example.com:80'))->willReturn(resolve($connection));
+        $this->tcp->expects($this->once())->method('connect')->with('example.com:80')->willReturn(resolve($connection));
 
         $promise = $this->connector->connect('example.com:80');
 
@@ -207,7 +213,7 @@ public function testConnectionWillBeRejectedIfStreamEncryptionFailsAndClosesConn
         });
 
         assert($exception instanceof \RuntimeException);
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         $this->assertEquals('Connection to tls://example.com:80 failed during TLS handshake: TLS error', $exception->getMessage());
         $this->assertEquals(123, $exception->getCode());
         $this->assertNull($exception->getPrevious());
@@ -216,13 +222,13 @@ public function testConnectionWillBeRejectedIfStreamEncryptionFailsAndClosesConn
 
     public function testCancelDuringStreamEncryptionCancelsEncryptionAndClosesConnection()
     {
-        $connection = $this->getMockBuilder('React\Socket\Connection')->disableOriginalConstructor()->getMock();
+        $connection = $this->createMock(Connection::class);
         $connection->expects($this->once())->method('close');
 
         $pending = new Promise(function () { }, function () {
             throw new \Exception('Ignored');
         });
-        $encryption = $this->getMockBuilder('React\Socket\StreamEncryption')->disableOriginalConstructor()->getMock();
+        $encryption = $this->createMock(StreamEncryption::class);
         $encryption->expects($this->once())->method('enable')->willReturn($pending);
 
         $ref = new \ReflectionProperty($this->connector, 'streamEncryption');
@@ -230,7 +236,7 @@ public function testCancelDuringStreamEncryptionCancelsEncryptionAndClosesConnec
         $ref->setValue($this->connector, $encryption);
 
         $deferred = new Deferred();
-        $this->tcp->expects($this->once())->method('connect')->with($this->equalTo('example.com:80'))->willReturn($deferred->promise());
+        $this->tcp->expects($this->once())->method('connect')->with('example.com:80')->willReturn($deferred->promise());
 
         $promise = $this->connector->connect('example.com:80');
         $deferred->resolve($connection);
@@ -243,7 +249,7 @@ public function testCancelDuringStreamEncryptionCancelsEncryptionAndClosesConnec
         });
 
         assert($exception instanceof \RuntimeException);
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         $this->assertEquals('Connection to tls://example.com:80 cancelled during TLS handshake (ECONNABORTED)', $exception->getMessage());
         $this->assertEquals(defined('SOCKET_ECONNABORTED') ? SOCKET_ECONNABORTED : 103, $exception->getCode());
         $this->assertNull($exception->getPrevious());
@@ -283,13 +289,13 @@ public function testRejectionDuringTlsHandshakeShouldNotCreateAnyGarbageReferenc
             // collect all garbage cycles
         }
 
-        $connection = $this->getMockBuilder('React\Socket\Connection')->disableOriginalConstructor()->getMock();
+        $connection = $this->createMock(Connection::class);
 
         $tcp = new Deferred();
         $this->tcp->expects($this->once())->method('connect')->willReturn($tcp->promise());
 
         $tls = new Deferred();
-        $encryption = $this->getMockBuilder('React\Socket\StreamEncryption')->disableOriginalConstructor()->getMock();
+        $encryption = $this->createMock(StreamEncryption::class);
         $encryption->expects($this->once())->method('enable')->willReturn($tls->promise());
 
         $ref = new \ReflectionProperty($this->connector, 'streamEncryption');
diff --git a/tests/SecureServerTest.php b/tests/SecureServerTest.php
index cfa2e72..ff569a6 100644
--- a/tests/SecureServerTest.php
+++ b/tests/SecureServerTest.php
@@ -2,16 +2,21 @@
 
 namespace React\Tests\Socket;
 
+use React\EventLoop\LoopInterface;
+use React\Promise\Promise;
+use React\Socket\ConnectionInterface;
+use React\Socket\Connection;
 use React\Socket\SecureServer;
+use React\Socket\ServerInterface;
+use React\Socket\StreamEncryption;
 use React\Socket\TcpServer;
-use React\Promise\Promise;
 use function React\Promise\reject;
 
 class SecureServerTest extends TestCase
 {
     public function testConstructWithoutLoopAssignsLoopAutomatically()
     {
-        $tcp = $this->getMockBuilder('React\Socket\ServerInterface')->getMock();
+        $tcp = $this->createMock(ServerInterface::class);
 
         $server = new SecureServer($tcp);
 
@@ -23,15 +28,15 @@ public function testConstructWithoutLoopAssignsLoopAutomatically()
         $ref->setAccessible(true);
         $loop = $ref->getValue($encryption);
 
-        $this->assertInstanceOf('React\EventLoop\LoopInterface', $loop);
+        $this->assertInstanceOf(LoopInterface::class, $loop);
     }
 
     public function testGetAddressWillBePassedThroughToTcpServer()
     {
-        $tcp = $this->getMockBuilder('React\Socket\ServerInterface')->getMock();
+        $tcp = $this->createMock(ServerInterface::class);
         $tcp->expects($this->once())->method('getAddress')->willReturn('tcp://127.0.0.1:1234');
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $server = new SecureServer($tcp, $loop, []);
 
@@ -40,10 +45,10 @@ public function testGetAddressWillBePassedThroughToTcpServer()
 
     public function testGetAddressWillReturnNullIfTcpServerReturnsNull()
     {
-        $tcp = $this->getMockBuilder('React\Socket\ServerInterface')->getMock();
+        $tcp = $this->createMock(ServerInterface::class);
         $tcp->expects($this->once())->method('getAddress')->willReturn(null);
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $server = new SecureServer($tcp, $loop, []);
 
@@ -52,10 +57,10 @@ public function testGetAddressWillReturnNullIfTcpServerReturnsNull()
 
     public function testPauseWillBePassedThroughToTcpServer()
     {
-        $tcp = $this->getMockBuilder('React\Socket\ServerInterface')->getMock();
+        $tcp = $this->createMock(ServerInterface::class);
         $tcp->expects($this->once())->method('pause');
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $server = new SecureServer($tcp, $loop, []);
 
@@ -64,10 +69,10 @@ public function testPauseWillBePassedThroughToTcpServer()
 
     public function testResumeWillBePassedThroughToTcpServer()
     {
-        $tcp = $this->getMockBuilder('React\Socket\ServerInterface')->getMock();
+        $tcp = $this->createMock(ServerInterface::class);
         $tcp->expects($this->once())->method('resume');
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $server = new SecureServer($tcp, $loop, []);
 
@@ -76,10 +81,10 @@ public function testResumeWillBePassedThroughToTcpServer()
 
     public function testCloseWillBePassedThroughToTcpServer()
     {
-        $tcp = $this->getMockBuilder('React\Socket\ServerInterface')->getMock();
+        $tcp = $this->createMock(ServerInterface::class);
         $tcp->expects($this->once())->method('close');
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $server = new SecureServer($tcp, $loop, []);
 
@@ -88,11 +93,11 @@ public function testCloseWillBePassedThroughToTcpServer()
 
     public function testConnectionWillBeClosedWithErrorIfItIsNotAStream()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $tcp = new TcpServer(0, $loop);
 
-        $connection = $this->getMockBuilder('React\Socket\ConnectionInterface')->getMock();
+        $connection = $this->createMock(ConnectionInterface::class);
         $connection->expects($this->once())->method('close');
 
         $server = new SecureServer($tcp, $loop, []);
@@ -104,11 +109,11 @@ public function testConnectionWillBeClosedWithErrorIfItIsNotAStream()
 
     public function testConnectionWillTryToEnableEncryptionAndWaitForHandshake()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $tcp = new TcpServer(0, $loop);
 
-        $connection = $this->getMockBuilder('React\Socket\Connection')->disableOriginalConstructor()->getMock();
+        $connection = $this->createMock(Connection::class);
         $connection->expects($this->once())->method('getRemoteAddress')->willReturn('tcp://127.0.0.1:1234');
         $connection->expects($this->never())->method('close');
 
@@ -116,7 +121,7 @@ public function testConnectionWillTryToEnableEncryptionAndWaitForHandshake()
 
         $pending = new Promise(function () { });
 
-        $encryption = $this->getMockBuilder('React\Socket\StreamEncryption')->disableOriginalConstructor()->getMock();
+        $encryption = $this->createMock(StreamEncryption::class);
         $encryption->expects($this->once())->method('enable')->willReturn($pending);
 
         $ref = new \ReflectionProperty($server, 'encryption');
@@ -135,11 +140,11 @@ public function testConnectionWillTryToEnableEncryptionAndWaitForHandshake()
 
     public function testConnectionWillBeClosedWithErrorIfEnablingEncryptionFails()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $tcp = new TcpServer(0, $loop);
 
-        $connection = $this->getMockBuilder('React\Socket\Connection')->disableOriginalConstructor()->getMock();
+        $connection = $this->createMock(Connection::class);
         $connection->expects($this->once())->method('getRemoteAddress')->willReturn('tcp://127.0.0.1:1234');
         $connection->expects($this->once())->method('close');
 
@@ -147,7 +152,7 @@ public function testConnectionWillBeClosedWithErrorIfEnablingEncryptionFails()
 
         $error = new \RuntimeException('Original');
 
-        $encryption = $this->getMockBuilder('React\Socket\StreamEncryption')->disableOriginalConstructor()->getMock();
+        $encryption = $this->createMock(StreamEncryption::class);
         $encryption->expects($this->once())->method('enable')->willReturn(reject($error));
 
         $ref = new \ReflectionProperty($server, 'encryption');
@@ -166,13 +171,13 @@ public function testConnectionWillBeClosedWithErrorIfEnablingEncryptionFails()
 
         $tcp->emit('connection', [$connection]);
 
-        $this->assertInstanceOf('RuntimeException', $error);
+        $this->assertInstanceOf(\RuntimeException::class, $error);
         $this->assertEquals('Connection from tcp://127.0.0.1:1234 failed during TLS handshake: Original', $error->getMessage());
     }
 
     public function testSocketErrorWillBeForwarded()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $tcp = new TcpServer(0, $loop);
 
diff --git a/tests/SocketServerTest.php b/tests/SocketServerTest.php
index 3ec87c7..537a2ce 100644
--- a/tests/SocketServerTest.php
+++ b/tests/SocketServerTest.php
@@ -2,6 +2,7 @@
 
 namespace React\Tests\Socket;
 
+use React\EventLoop\LoopInterface;
 use React\Promise\Promise;
 use React\Socket\ConnectionInterface;
 use React\Socket\SocketServer;
@@ -28,7 +29,7 @@ public function testConstructWithoutLoopAssignsLoopAutomatically()
         $ref->setAccessible(true);
         $loop = $ref->getValue($tcp);
 
-        $this->assertInstanceOf('React\EventLoop\LoopInterface', $loop);
+        $this->assertInstanceOf(LoopInterface::class, $loop);
     }
 
     public function testCreateServerWithZeroPortAssignsRandomPort()
@@ -40,31 +41,25 @@ public function testCreateServerWithZeroPortAssignsRandomPort()
 
     public function testConstructorWithInvalidUriThrows()
     {
-        $this->setExpectedException(
-            'InvalidArgumentException',
-            'Invalid URI "tcp://invalid URI" given (EINVAL)',
-            defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
-        );
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Invalid URI "tcp://invalid URI" given (EINVAL)');
+        $this->expectExceptionCode(defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22));
         new SocketServer('invalid URI');
     }
 
     public function testConstructorWithInvalidUriWithPortOnlyThrows()
     {
-        $this->setExpectedException(
-            'InvalidArgumentException',
-            'Invalid URI given (EINVAL)',
-            defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
-        );
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Invalid URI given (EINVAL)');
+        $this->expectExceptionCode(defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22));
         new SocketServer('0');
     }
 
     public function testConstructorWithInvalidUriWithSchemaAndPortOnlyThrows()
     {
-        $this->setExpectedException(
-            'InvalidArgumentException',
-            'Invalid URI given (EINVAL)',
-            defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
-        );
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Invalid URI given (EINVAL)');
+        $this->expectExceptionCode(defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22));
         new SocketServer('tcp://0');
     }
 
diff --git a/tests/Stub/CallableStub.php b/tests/Stub/CallableStub.php
deleted file mode 100644
index 1b197eb..0000000
--- a/tests/Stub/CallableStub.php
+++ /dev/null
@@ -1,10 +0,0 @@
-<?php
-
-namespace React\Tests\Socket\Stub;
-
-class CallableStub
-{
-    public function __invoke()
-    {
-    }
-}
diff --git a/tests/TcpConnectorTest.php b/tests/TcpConnectorTest.php
index 48062a9..9858beb 100644
--- a/tests/TcpConnectorTest.php
+++ b/tests/TcpConnectorTest.php
@@ -2,9 +2,12 @@
 
 namespace React\Tests\Socket;
 
+use PHPUnit\Framework\Error\Warning;
 use React\EventLoop\Loop;
+use React\EventLoop\LoopInterface;
 use React\Promise\Promise;
 use React\Socket\ConnectionInterface;
+use React\Socket\SocketServer;
 use React\Socket\TcpConnector;
 use React\Socket\TcpServer;
 use function React\Async\await;
@@ -22,7 +25,7 @@ public function testConstructWithoutLoopAssignsLoopAutomatically()
         $ref->setAccessible(true);
         $loop = $ref->getValue($connector);
 
-        $this->assertInstanceOf('React\EventLoop\LoopInterface', $loop);
+        $this->assertInstanceOf(LoopInterface::class, $loop);
     }
 
     /** @test */
@@ -36,11 +39,9 @@ public function connectionToEmptyPortShouldFailWithoutCallingCustomErrorHandler(
             $error = $errstr;
         });
 
-        $this->setExpectedException(
-            'RuntimeException',
-            'Connection to tcp://127.0.0.1:9999 failed: Connection refused' . (function_exists('socket_import_stream') ? ' (ECONNREFUSED)' : ''),
-            defined('SOCKET_ECONNREFUSED') ? SOCKET_ECONNREFUSED : 111
-        );
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('Connection to tcp://127.0.0.1:9999 failed: Connection refused' . (function_exists('socket_import_stream') ? ' (ECONNREFUSED)' : ''));
+        $this->expectExceptionCode(defined('SOCKET_ECONNREFUSED') ? SOCKET_ECONNREFUSED : 111);
 
         try {
             await(timeout($promise, self::TIMEOUT));
@@ -57,7 +58,7 @@ public function connectionToEmptyPortShouldFailWithoutCallingCustomErrorHandler(
     /** @test */
     public function connectionToTcpServerShouldAddResourceToLoop()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $connector = new TcpConnector($loop);
 
         $server = new TcpServer(0, $loop);
@@ -81,7 +82,7 @@ public function connectionToTcpServerShouldSucceed()
 
         $connection = await(timeout($connector->connect('127.0.0.1:9999'), self::TIMEOUT));
 
-        $this->assertInstanceOf('React\Socket\ConnectionInterface', $connection);
+        $this->assertInstanceOf(ConnectionInterface::class, $connection);
 
         $connection->close();
         $server->close();
@@ -116,8 +117,8 @@ public function connectionToTcpServerShouldFailIfFileDescriptorsAreExceeded()
         }
 
         // dummy rejected promise to make sure autoloader has initialized all classes
-        class_exists('React\Socket\SocketServer', true);
-        class_exists('PHPUnit\Framework\Error\Warning', true);
+        class_exists(SocketServer::class, true);
+        class_exists(Warning::class, true);
         $promise = new Promise(function () { throw new \RuntimeException('dummy'); });
         $promise->then(null, $this->expectCallableOnce()); // avoid reporting unhandled rejection
         unset($promise);
@@ -132,7 +133,7 @@ class_exists('PHPUnit\Framework\Error\Warning', true);
             $fds[] = $fd;
         }
 
-        $this->setExpectedException('RuntimeException');
+        $this->expectException(\RuntimeException::class);
         await(timeout($connector->connect('127.0.0.1:9999'), self::TIMEOUT));
     }
 
@@ -160,11 +161,9 @@ public function connectionToInvalidNetworkShouldFailWithUnreachableError()
 
         $promise = $connector->connect($address);
 
-        $this->setExpectedException(
-            'RuntimeException',
-            'Connection to ' . $address . ' failed: ' . (function_exists('socket_strerror') ? socket_strerror($enetunreach) . ' (ENETUNREACH)' : 'Network is unreachable'),
-            $enetunreach
-        );
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('Connection to ' . $address . ' failed: ' . (function_exists('socket_strerror') ? socket_strerror($enetunreach) . ' (ENETUNREACH)' : 'Network is unreachable'));
+        $this->expectExceptionCode($enetunreach);
         await(timeout($promise, self::TIMEOUT));
     }
 
@@ -194,7 +193,7 @@ public function connectionToTcpServerShouldSucceedWithLocalAdressOnLocalhost()
         $connection = await(timeout($connector->connect('127.0.0.1:9999'), self::TIMEOUT));
         /* @var $connection ConnectionInterface */
 
-        $this->assertContainsString('tcp://127.0.0.1:', $connection->getLocalAddress());
+        $this->assertStringContainsString('tcp://127.0.0.1:', $connection->getLocalAddress());
         $this->assertNotEquals('tcp://127.0.0.1:9999', $connection->getLocalAddress());
 
         $connection->close();
@@ -267,7 +266,7 @@ public function connectionToIp6TcpServerShouldSucceed()
 
         $this->assertEquals('tcp://[::1]:9999', $connection->getRemoteAddress());
 
-        $this->assertContainsString('tcp://[::1]:', $connection->getLocalAddress());
+        $this->assertStringContainsString('tcp://[::1]:', $connection->getLocalAddress());
         $this->assertNotEquals('tcp://[::1]:9999', $connection->getLocalAddress());
 
         $connection->close();
@@ -277,13 +276,13 @@ public function connectionToIp6TcpServerShouldSucceed()
     /** @test */
     public function connectionToHostnameShouldFailImmediately()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $connector = new TcpConnector($loop);
         $promise = $connector->connect('www.google.com:80');
 
         $promise->then(null, $this->expectCallableOnceWithException(
-            'InvalidArgumentException',
+            \InvalidArgumentException::class,
             'Given URI "tcp://www.google.com:80" does not contain a valid host IP (EINVAL)',
             defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
         ));
@@ -292,13 +291,13 @@ public function connectionToHostnameShouldFailImmediately()
     /** @test */
     public function connectionToInvalidPortShouldFailImmediately()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $connector = new TcpConnector($loop);
         $promise = $connector->connect('255.255.255.255:12345678');
 
         $promise->then(null, $this->expectCallableOnceWithException(
-            'InvalidArgumentException',
+            \InvalidArgumentException::class,
             'Given URI "tcp://255.255.255.255:12345678" is invalid (EINVAL)',
             defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
         ));
@@ -307,7 +306,7 @@ public function connectionToInvalidPortShouldFailImmediately()
     /** @test */
     public function connectionToInvalidSchemeShouldFailImmediately()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $connector = new TcpConnector($loop);
         $connector->connect('tls://google.com:443')->then(
@@ -319,7 +318,7 @@ public function connectionToInvalidSchemeShouldFailImmediately()
     /** @test */
     public function cancellingConnectionShouldRemoveResourceFromLoopAndCloseResource()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $connector = new TcpConnector($loop);
 
         $server = new TcpServer(0, $loop);
@@ -354,11 +353,9 @@ public function cancellingConnectionShouldRejectPromise()
         $promise = $connector->connect($server->getAddress());
         $promise->cancel();
 
-        $this->setExpectedException(
-            'RuntimeException',
-            'Connection to ' . $server->getAddress() . ' cancelled during TCP/IP handshake (ECONNABORTED)',
-            defined('SOCKET_ECONNABORTED') ? SOCKET_ECONNABORTED : 103
-        );
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('Connection to ' . $server->getAddress() . ' cancelled during TCP/IP handshake (ECONNABORTED)');
+        $this->expectExceptionCode(defined('SOCKET_ECONNABORTED') ? SOCKET_ECONNABORTED : 103);
 
         try {
             await($promise);
@@ -378,7 +375,7 @@ public function testCancelDuringConnectionShouldNotCreateAnyGarbageReferences()
             // collect all garbage cycles
         }
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $connector = new TcpConnector($loop);
         $promise = $connector->connect('127.0.0.1:9999');
 
diff --git a/tests/TcpServerTest.php b/tests/TcpServerTest.php
index 7f052c3..1adf91b 100644
--- a/tests/TcpServerTest.php
+++ b/tests/TcpServerTest.php
@@ -3,7 +3,9 @@
 namespace React\Tests\Socket;
 
 use React\EventLoop\Loop;
+use React\EventLoop\LoopInterface;
 use React\Promise\Promise;
+use React\Socket\ConnectionInterface;
 use React\Socket\TcpServer;
 use React\Stream\DuplexResourceStream;
 use function React\Async\await;
@@ -37,7 +39,7 @@ public function testConstructWithoutLoopAssignsLoopAutomatically()
         $ref->setAccessible(true);
         $loop = $ref->getValue($server);
 
-        $this->assertInstanceOf('React\EventLoop\LoopInterface', $loop);
+        $this->assertInstanceOf(LoopInterface::class, $loop);
 
         $server->close();
     }
@@ -56,7 +58,7 @@ public function testServerEmitsConnectionEventForNewConnection()
 
         $connection = await(timeout($promise, self::TIMEOUT));
 
-        $this->assertInstanceOf('React\Socket\ConnectionInterface', $connection);
+        $this->assertInstanceOf(ConnectionInterface::class, $connection);
     }
 
     /**
@@ -235,7 +237,7 @@ public function testConnectionDoesEndWhenClientCloses()
 
     public function testCtorAddsResourceToLoop()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addReadStream');
 
         new TcpServer(0, $loop);
@@ -243,7 +245,7 @@ public function testCtorAddsResourceToLoop()
 
     public function testResumeWithoutPauseIsNoOp()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addReadStream');
 
         $server = new TcpServer(0, $loop);
@@ -252,7 +254,7 @@ public function testResumeWithoutPauseIsNoOp()
 
     public function testPauseRemovesResourceFromLoop()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('removeReadStream');
 
         $server = new TcpServer(0, $loop);
@@ -261,7 +263,7 @@ public function testPauseRemovesResourceFromLoop()
 
     public function testPauseAfterPauseIsNoOp()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('removeReadStream');
 
         $server = new TcpServer(0, $loop);
@@ -271,7 +273,7 @@ public function testPauseAfterPauseIsNoOp()
 
     public function testCloseRemovesResourceFromLoop()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('removeReadStream');
 
         $server = new TcpServer(0, $loop);
@@ -281,7 +283,7 @@ public function testCloseRemovesResourceFromLoop()
     public function testEmitsErrorWhenAcceptListenerFailsWithoutCallingCustomErrorHandler()
     {
         $listener = null;
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addReadStream')->with($this->anything(), $this->callback(function ($cb) use (&$listener) {
             $listener = $cb;
             return true;
@@ -311,7 +313,7 @@ public function testEmitsErrorWhenAcceptListenerFailsWithoutCallingCustomErrorHa
 
         $this->assertLessThan(1, $time);
 
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         assert($exception instanceof \RuntimeException);
         $this->assertStringStartsWith('Unable to accept new connection: ', $exception->getMessage());
 
@@ -335,11 +337,9 @@ public function testListenOnBusyPortThrows()
             $this->markTestSkipped('Windows supports listening on same port multiple times');
         }
 
-        $this->setExpectedException(
-            'RuntimeException',
-            'Failed to listen on "tcp://127.0.0.1:' . $this->port . '": ' . (function_exists('socket_strerror') ? socket_strerror(SOCKET_EADDRINUSE) . ' (EADDRINUSE)' : 'Address already in use'),
-            defined('SOCKET_EADDRINUSE') ? SOCKET_EADDRINUSE : 0
-        );
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessage('Failed to listen on "tcp://127.0.0.1:' . $this->port . '": ' . (function_exists('socket_strerror') ? socket_strerror(SOCKET_EADDRINUSE) . ' (EADDRINUSE)' : 'Address already in use'));
+        $this->expectExceptionCode(defined('SOCKET_EADDRINUSE') ? SOCKET_EADDRINUSE : 0);
         new TcpServer($this->port);
     }
 
diff --git a/tests/TestCase.php b/tests/TestCase.php
index d707db0..1e7a79e 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -69,7 +69,14 @@ protected function expectCallableNever()
 
     protected function createCallableMock()
     {
-        return $this->getMockBuilder('React\Tests\Socket\Stub\CallableStub')->getMock();
+        $builder = $this->getMockBuilder(\stdClass::class);
+        if (method_exists($builder, 'addMethods')) {
+            // PHPUnit 9+
+            return $builder->addMethods(['__invoke'])->getMock();
+        } else {
+            // legacy PHPUnit
+            return $builder->setMethods(['__invoke'])->getMock();
+        }
     }
 
     protected function buffer(ReadableStreamInterface $stream, $timeout)
@@ -106,17 +113,6 @@ function () use ($stream) {
         return $buffer;
     }
 
-    public function setExpectedException($exception, $exceptionMessage = '', $exceptionCode = null)
-    {
-        $this->expectException($exception);
-        if ($exceptionMessage !== '') {
-            $this->expectExceptionMessage($exceptionMessage);
-        }
-        if ($exceptionCode !== null) {
-            $this->expectExceptionCode($exceptionCode);
-        }
-    }
-
     protected function supportsTls13()
     {
         // TLS 1.3 is supported as of OpenSSL 1.1.1 (https://www.openssl.org/blog/blog/2018/09/11/release111/)
@@ -133,37 +129,4 @@ protected function supportsTls13()
         }
         return false;
     }
-
-    public function assertContainsString($needle, $haystack)
-    {
-        if (method_exists($this, 'assertStringContainsString')) {
-            // PHPUnit 7.5+
-            $this->assertStringContainsString($needle, $haystack);
-        } else {
-            // legacy PHPUnit 4- PHPUnit 7.5
-            $this->assertContains($needle, $haystack);
-        }
-    }
-
-    public function assertMatchesRegExp($pattern, $string)
-    {
-        if (method_exists($this, 'assertMatchesRegularExpression')) {
-            // PHPUnit 10
-            $this->assertMatchesRegularExpression($pattern, $string);
-        } else {
-            // legacy PHPUnit 4 - PHPUnit 9.2
-            $this->assertRegExp($pattern, $string);
-        }
-    }
-
-    public function assertDoesNotMatchRegExp($pattern, $string)
-    {
-        if (method_exists($this, 'assertDoesNotMatchRegularExpression')) {
-            // PHPUnit 10
-            $this->assertDoesNotMatchRegularExpression($pattern, $string);
-        } else {
-            // legacy PHPUnit 4 - PHPUnit 9.2
-            $this->assertNotRegExp($pattern, $string);
-        }
-    }
 }
diff --git a/tests/TimeoutConnectorTest.php b/tests/TimeoutConnectorTest.php
index f4c5dfc..e121cab 100644
--- a/tests/TimeoutConnectorTest.php
+++ b/tests/TimeoutConnectorTest.php
@@ -3,8 +3,12 @@
 namespace React\Tests\Socket;
 
 use React\EventLoop\Loop;
+use React\EventLoop\LoopInterface;
+use React\EventLoop\TimerInterface;
 use React\Promise\Deferred;
 use React\Promise\Promise;
+use React\Socket\ConnectionInterface;
+use React\Socket\ConnectorInterface;
 use React\Socket\TimeoutConnector;
 use function React\Promise\reject;
 use function React\Promise\resolve;
@@ -13,7 +17,7 @@ class TimeoutConnectorTest extends TestCase
 {
     public function testConstructWithoutLoopAssignsLoopAutomatically()
     {
-        $base = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $base = $this->createMock(ConnectorInterface::class);
 
         $connector = new TimeoutConnector($base, 0.01);
 
@@ -21,16 +25,16 @@ public function testConstructWithoutLoopAssignsLoopAutomatically()
         $ref->setAccessible(true);
         $loop = $ref->getValue($connector);
 
-        $this->assertInstanceOf('React\EventLoop\LoopInterface', $loop);
+        $this->assertInstanceOf(LoopInterface::class, $loop);
     }
 
     public function testRejectsPromiseWithoutStartingTimerWhenWrappedConnectorReturnsRejectedPromise()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->never())->method('addTimer');
         $loop->expects($this->never())->method('cancelTimer');
 
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('example.com:80')->willReturn(reject(new \RuntimeException('Failed', 42)));
 
         $timeout = new TimeoutConnector($connector, 5.0, $loop);
@@ -49,13 +53,13 @@ public function testRejectsPromiseWithoutStartingTimerWhenWrappedConnectorReturn
 
     public function testRejectsPromiseAfterCancellingTimerWhenWrappedConnectorReturnsPendingPromiseThatRejects()
     {
-        $timer = $this->getMockBuilder('React\EventLoop\TimerInterface')->getMock();
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $timer = $this->createMock(TimerInterface::class);
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->with(5.0, $this->anything())->willReturn($timer);
         $loop->expects($this->once())->method('cancelTimer')->with($timer);
 
         $deferred = new Deferred();
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('example.com:80')->willReturn($deferred->promise());
 
         $timeout = new TimeoutConnector($connector, 5.0, $loop);
@@ -76,12 +80,12 @@ public function testRejectsPromiseAfterCancellingTimerWhenWrappedConnectorReturn
 
     public function testResolvesPromiseWithoutStartingTimerWhenWrappedConnectorReturnsResolvedPromise()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->never())->method('addTimer');
         $loop->expects($this->never())->method('cancelTimer');
 
-        $connection = $this->getMockBuilder('React\Socket\ConnectionInterface')->getMock();
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connection = $this->createMock(ConnectionInterface::class);
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('example.com:80')->willReturn(resolve($connection));
 
         $timeout = new TimeoutConnector($connector, 5.0, $loop);
@@ -98,20 +102,20 @@ public function testResolvesPromiseWithoutStartingTimerWhenWrappedConnectorRetur
 
     public function testResolvesPromiseAfterCancellingTimerWhenWrappedConnectorReturnsPendingPromiseThatResolves()
     {
-        $timer = $this->getMockBuilder('React\EventLoop\TimerInterface')->getMock();
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $timer = $this->createMock(TimerInterface::class);
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->with(5.0, $this->anything())->willReturn($timer);
         $loop->expects($this->once())->method('cancelTimer')->with($timer);
 
         $deferred = new Deferred();
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('example.com:80')->willReturn($deferred->promise());
 
         $timeout = new TimeoutConnector($connector, 5.0, $loop);
 
         $promise = $timeout->connect('example.com:80');
 
-        $connection = $this->getMockBuilder('React\Socket\ConnectionInterface')->getMock();
+        $connection = $this->createMock(ConnectionInterface::class);
         $deferred->resolve($connection);
 
         $resolved = null;
@@ -125,8 +129,8 @@ public function testResolvesPromiseAfterCancellingTimerWhenWrappedConnectorRetur
     public function testRejectsPromiseAndCancelsPendingConnectionWhenTimeoutTriggers()
     {
         $timerCallback = null;
-        $timer = $this->getMockBuilder('React\EventLoop\TimerInterface')->getMock();
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $timer = $this->createMock(TimerInterface::class);
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->with(0.01, $this->callback(function ($callback) use (&$timerCallback) {
             $timerCallback = $callback;
             return true;
@@ -134,7 +138,7 @@ public function testRejectsPromiseAndCancelsPendingConnectionWhenTimeoutTriggers
         $loop->expects($this->once())->method('cancelTimer')->with($timer);
 
         $cancelled = 0;
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('example.com:80')->willReturn(new Promise(function () { }, function () use (&$cancelled) {
             ++$cancelled;
             throw new \RuntimeException();
@@ -163,13 +167,13 @@ public function testRejectsPromiseAndCancelsPendingConnectionWhenTimeoutTriggers
 
     public function testCancellingPromiseWillCancelPendingConnectionAndRejectPromise()
     {
-        $timer = $this->getMockBuilder('React\EventLoop\TimerInterface')->getMock();
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $timer = $this->createMock(TimerInterface::class);
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addTimer')->with(0.01, $this->anything())->willReturn($timer);
         $loop->expects($this->once())->method('cancelTimer')->with($timer);
 
         $cancelled = 0;
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('example.com:80')->willReturn(new Promise(function () { }, function () use (&$cancelled) {
             ++$cancelled;
             throw new \RuntimeException('Cancelled');
@@ -206,7 +210,7 @@ public function testRejectionDuringConnectionShouldNotCreateAnyGarbageReferences
         }
 
         $connection = new Deferred();
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('example.com:80')->willReturn($connection->promise());
 
         $timeout = new TimeoutConnector($connector, 0.01);
@@ -234,7 +238,7 @@ public function testRejectionDueToTimeoutShouldNotCreateAnyGarbageReferences()
         $connection = new Deferred(function () {
             throw new \RuntimeException('Connection cancelled');
         });
-        $connector = $this->getMockBuilder('React\Socket\ConnectorInterface')->getMock();
+        $connector = $this->createMock(ConnectorInterface::class);
         $connector->expects($this->once())->method('connect')->with('example.com:80')->willReturn($connection->promise());
 
         $timeout = new TimeoutConnector($connector, 0);
diff --git a/tests/UnixConnectorTest.php b/tests/UnixConnectorTest.php
index d7e314a..ad6b757 100644
--- a/tests/UnixConnectorTest.php
+++ b/tests/UnixConnectorTest.php
@@ -2,6 +2,7 @@
 
 namespace React\Tests\Socket;
 
+use React\EventLoop\LoopInterface;
 use React\Socket\ConnectionInterface;
 use React\Socket\UnixConnector;
 
@@ -15,7 +16,7 @@ class UnixConnectorTest extends TestCase
      */
     public function setUpConnector()
     {
-        $this->loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $this->loop = $this->createMock(LoopInterface::class);
         $this->connector = new UnixConnector($this->loop);
     }
 
@@ -27,7 +28,7 @@ public function testConstructWithoutLoopAssignsLoopAutomatically()
         $ref->setAccessible(true);
         $loop = $ref->getValue($connector);
 
-        $this->assertInstanceOf('React\EventLoop\LoopInterface', $loop);
+        $this->assertInstanceOf(LoopInterface::class, $loop);
     }
 
     public function testInvalid()
@@ -35,7 +36,7 @@ public function testInvalid()
         $promise = $this->connector->connect('google.com:80');
 
         $promise->then(null, $this->expectCallableOnceWithException(
-            'RuntimeException'
+            \RuntimeException::class
         ));
     }
 
@@ -44,7 +45,7 @@ public function testInvalidScheme()
         $promise = $this->connector->connect('tcp://google.com:80');
 
         $promise->then(null, $this->expectCallableOnceWithException(
-            'InvalidArgumentException',
+            \InvalidArgumentException::class,
             'Given URI "tcp://google.com:80" is invalid (EINVAL)',
             defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
         ));
diff --git a/tests/UnixServerTest.php b/tests/UnixServerTest.php
index 6d972b9..0e71cef 100644
--- a/tests/UnixServerTest.php
+++ b/tests/UnixServerTest.php
@@ -3,6 +3,7 @@
 namespace React\Tests\Socket;
 
 use React\EventLoop\Loop;
+use React\EventLoop\LoopInterface;
 use React\Socket\UnixServer;
 use React\Stream\DuplexResourceStream;
 use function React\Async\await;
@@ -42,7 +43,7 @@ public function testConstructWithoutLoopAssignsLoopAutomatically()
         $ref->setAccessible(true);
         $loop = $ref->getValue($server);
 
-        $this->assertInstanceOf('React\EventLoop\LoopInterface', $loop);
+        $this->assertInstanceOf(LoopInterface::class, $loop);
 
         $server->close();
     }
@@ -241,7 +242,7 @@ public function testCtorAddsResourceToLoop()
         unlink(str_replace('unix://', '', $this->uds));
         $this->uds = $this->getRandomSocketUri();
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addReadStream');
 
         new UnixServer($this->uds, $loop);
@@ -249,26 +250,24 @@ public function testCtorAddsResourceToLoop()
 
     public function testCtorThrowsForInvalidAddressScheme()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
-        $this->setExpectedException(
-            'InvalidArgumentException',
-            'Given URI "tcp://localhost:0" is invalid (EINVAL)',
-            defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22)
-        );
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Given URI "tcp://localhost:0" is invalid (EINVAL)');
+        $this->expectExceptionCode(defined('SOCKET_EINVAL') ? SOCKET_EINVAL : (defined('PCNTL_EINVAL') ? PCNTL_EINVAL : 22));
         new UnixServer('tcp://localhost:0', $loop);
     }
 
     public function testCtorThrowsWhenPathIsNotWritableWithoutCallingCustomErrorHandler()
     {
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
 
         $error = null;
         set_error_handler(function ($_, $errstr) use (&$error) {
             $error = $errstr;
         });
 
-        $this->setExpectedException('RuntimeException');
+        $this->expectException(\RuntimeException::class);
 
         try {
             new UnixServer('/dev/null', $loop);
@@ -287,7 +286,7 @@ public function testResumeWithoutPauseIsNoOp()
         unlink(str_replace('unix://', '', $this->uds));
         $this->uds = $this->getRandomSocketUri();
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addReadStream');
 
         $server = new UnixServer($this->uds, $loop);
@@ -299,7 +298,7 @@ public function testPauseRemovesResourceFromLoop()
         unlink(str_replace('unix://', '', $this->uds));
         $this->uds = $this->getRandomSocketUri();
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('removeReadStream');
 
         $server = new UnixServer($this->uds, $loop);
@@ -311,7 +310,7 @@ public function testPauseAfterPauseIsNoOp()
         unlink(str_replace('unix://', '', $this->uds));
         $this->uds = $this->getRandomSocketUri();
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('removeReadStream');
 
         $server = new UnixServer($this->uds, $loop);
@@ -324,7 +323,7 @@ public function testCloseRemovesResourceFromLoop()
         unlink(str_replace('unix://', '', $this->uds));
         $this->uds = $this->getRandomSocketUri();
 
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('removeReadStream');
 
         $server = new UnixServer($this->uds, $loop);
@@ -337,7 +336,7 @@ public function testEmitsErrorWhenAcceptListenerFailsWithoutCallingCustomErrorHa
         $this->uds = $this->getRandomSocketUri();
 
         $listener = null;
-        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop = $this->createMock(LoopInterface::class);
         $loop->expects($this->once())->method('addReadStream')->with($this->anything(), $this->callback(function ($cb) use (&$listener) {
             $listener = $cb;
             return true;
@@ -367,7 +366,7 @@ public function testEmitsErrorWhenAcceptListenerFailsWithoutCallingCustomErrorHa
 
         $this->assertLessThan(1, $time);
 
-        $this->assertInstanceOf('RuntimeException', $exception);
+        $this->assertInstanceOf(\RuntimeException::class, $exception);
         assert($exception instanceof \RuntimeException);
         $this->assertStringStartsWith('Unable to accept new connection: ', $exception->getMessage());
 
@@ -391,7 +390,7 @@ public function testListenOnBusyPortThrows()
             $this->markTestSkipped('Windows supports listening on same port multiple times');
         }
 
-        $this->setExpectedException('RuntimeException');
+        $this->expectException(\RuntimeException::class);
         new UnixServer($this->uds);
     }