diff --git a/StyleCop.Analyzers/StyleCop.Analyzers.Test/OrderingRules/SA1200UnitTests.cs b/StyleCop.Analyzers/StyleCop.Analyzers.Test/OrderingRules/SA1200UnitTests.cs
new file mode 100644
index 000000000..c7dbf8e36
--- /dev/null
+++ b/StyleCop.Analyzers/StyleCop.Analyzers.Test/OrderingRules/SA1200UnitTests.cs
@@ -0,0 +1,134 @@
+namespace StyleCop.Analyzers.Test.OrderingRules
+{
+    using System.Collections.Generic;
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis.Diagnostics;
+    using StyleCop.Analyzers.OrderingRules;
+    using TestHelper;
+    using Xunit;
+
+    /// <summary>
+    /// Unit tests for the <see cref="SA1200UsingDirectivesMustBePlacedWithinNamespace"/>
+    /// </summary>
+    public class SA1200UnitTests : DiagnosticVerifier
+    {
+        private const string ClassDefinition = @"public class TestClass
+{
+}";
+
+        private const string StructDefinition = @"public struct TestStruct
+{
+}";
+
+        private const string InterfaceDefinition = @"public interface TestInterface
+{
+}";
+
+        private const string EnumDefinition = @"public enum TestEnum
+{
+    TestValue
+}";
+
+        private const string DelegateDefinition = @"public delegate void TestDelegate();";
+
+        /// <summary>
+        /// Verify that the analyzer accepts an empty source.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        public async Task TestEmptySourceAsync()
+        {
+            var testCode = string.Empty;
+            await this.VerifyCSharpDiagnosticAsync(testCode, EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// Verifies that valid using statements in a namespace does not produce any diagnostics.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        public async Task TestValidUsingStatementsInNamespaceAsync()
+        {
+            var testCode = @"namespace TestNamespace
+{
+    using System;
+    using System.Threading;
+}
+";
+
+            await this.VerifyCSharpDiagnosticAsync(testCode, EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// Verifies that having using statements in the compilation unit will not produce any diagnostics when there are type definition present.
+        /// </summary>
+        /// <param name="typeDefinition">The type definition to test.</param>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Theory]
+        [InlineData(ClassDefinition)]
+        [InlineData(StructDefinition)]
+        [InlineData(InterfaceDefinition)]
+        [InlineData(EnumDefinition)]
+        [InlineData(DelegateDefinition)]
+        public async Task TestValidUsingStatementsInCompilationUnitWithTypeDefinitionAsync(string typeDefinition)
+        {
+            var testCode = $@"using System;
+
+{typeDefinition}
+";
+
+            await this.VerifyCSharpDiagnosticAsync(testCode, EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// Verifies that having using statements in the compilation unit will not produce any diagnostics when there are attributes present.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        public async Task TestValidUsingStatementsInCompilationUnitWithAttributesAsync()
+        {
+            var testCode = @"using System.Reflection;
+
+[assembly: AssemblyVersion(""1.0.0.0"")]
+
+namespace TestNamespace
+{
+    using System;
+    using System.Threading;
+}
+";
+
+            await this.VerifyCSharpDiagnosticAsync(testCode, EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// Verifies that having using statements in the compilation unit will produce the expected diagnostics.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        public async Task TestInvalidUsingStatementsInCompilationUnitAsync()
+        {
+            var testCode = @"using System;
+using System.Threading;
+
+namespace TestNamespace
+{
+}
+";
+
+            DiagnosticResult[] expectedResults =
+            {
+                this.CSharpDiagnostic().WithLocation(1, 1),
+                this.CSharpDiagnostic().WithLocation(2, 1)
+            };
+
+            await this.VerifyCSharpDiagnosticAsync(testCode, expectedResults, CancellationToken.None).ConfigureAwait(false);
+        }
+
+        protected override IEnumerable<DiagnosticAnalyzer> GetCSharpDiagnosticAnalyzers()
+        {
+            yield return new SA1200UsingDirectivesMustBePlacedWithinNamespace();
+        }
+    }
+}
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers.Test/StyleCop.Analyzers.Test.csproj b/StyleCop.Analyzers/StyleCop.Analyzers.Test/StyleCop.Analyzers.Test.csproj
index 381c508ad..4b5312a5b 100644
--- a/StyleCop.Analyzers/StyleCop.Analyzers.Test/StyleCop.Analyzers.Test.csproj
+++ b/StyleCop.Analyzers/StyleCop.Analyzers.Test/StyleCop.Analyzers.Test.csproj
@@ -235,6 +235,7 @@
     <Compile Include="NamingRules\SA1311UnitTests.cs" />
     <Compile Include="NamingRules\SX1309SUnitTests.cs" />
     <Compile Include="NamingRules\SX1309UnitTests.cs" />
+    <Compile Include="OrderingRules\SA1200UnitTests.cs" />
     <Compile Include="OrderingRules\SA1201UnitTests.cs" />
     <Compile Include="OrderingRules\SA1205UnitTests.cs" />
     <Compile Include="OrderingRules\SA1208UnitTests.cs" />
diff --git a/StyleCop.Analyzers/StyleCop.Analyzers/OrderingRules/SA1200UsingDirectivesMustBePlacedWithinNamespace.cs b/StyleCop.Analyzers/StyleCop.Analyzers/OrderingRules/SA1200UsingDirectivesMustBePlacedWithinNamespace.cs
index 4970ebb4a..43dac6908 100644
--- a/StyleCop.Analyzers/StyleCop.Analyzers/OrderingRules/SA1200UsingDirectivesMustBePlacedWithinNamespace.cs
+++ b/StyleCop.Analyzers/StyleCop.Analyzers/OrderingRules/SA1200UsingDirectivesMustBePlacedWithinNamespace.cs
@@ -159,7 +159,7 @@ public class SA1200UsingDirectivesMustBePlacedWithinNamespace : DiagnosticAnalyz
         private const string HelpLink = "http://www.stylecop.com/docs/SA1200.html";
 
         private static readonly DiagnosticDescriptor Descriptor =
-            new DiagnosticDescriptor(DiagnosticId, Title, MessageFormat, Category, DiagnosticSeverity.Warning, AnalyzerConstants.DisabledNoTests, Description, HelpLink);
+            new DiagnosticDescriptor(DiagnosticId, Title, MessageFormat, Category, DiagnosticSeverity.Warning, AnalyzerConstants.EnabledByDefault, Description, HelpLink);
 
         private static readonly ImmutableArray<DiagnosticDescriptor> SupportedDiagnosticsValue =
             ImmutableArray.Create(Descriptor);