Add patch to stop tests flaking while using host machines termainal.

Patch the "getTerminal" with nil to stop the terminal of the host
machine being used by default.

ssh/export_test.go

@@ -37,3 +37,9 @@ func PatchTerminal(s *testing.CleanupSuite, rlw ReadLineWriter) {
 		c.Assert(atomic.LoadInt64(&balance), gc.Equals, int64(0))
 	})
 }
+
+func PatchNilTerminal(s *testing.CleanupSuite) {
+	s.PatchValue(&getTerminal, func() (readLineWriter, func(), error) {
+		return nil, func() {}, nil
+	})
+}

ssh/ssh_gocrypto_test.go

@@ -154,12 +154,9 @@ func (s *SSHGoCryptoCommandSuite) SetUpTest(c *gc.C) {
 	generateKeyRestorer := overrideGenerateKey(c)
 	s.AddCleanup(func(*gc.C) { generateKeyRestorer.Restore() })
 
-	client, err := ssh.NewGoCryptoClient()
-	c.Assert(err, jc.ErrorIsNil)
-	s.client = client
-
 	s.knownHostsFile = filepath.Join(c.MkDir(), "known_hosts")
 	ssh.SetGoCryptoKnownHostsFile(s.knownHostsFile)
+	ssh.PatchNilTerminal(&s.CleanupSuite)
 }
 
 func (s *SSHGoCryptoCommandSuite) newServer(c *gc.C, serverConfig cryptossh.ServerConfig) (*sshServer, cryptossh.PublicKey) {