Method TestTLS_DisabledALPNClient

credentials/tls_ext_test.go:455–532

TestTLS_DisabledALPNClient tests the behaviour of TransportCredentials when connecting to a server that doesn't support ALPN.

(t *testing.T)

// TestTLS_DisabledALPNClient tests the behaviour of TransportCredentials when
// connecting to a server that doesn't support ALPN.
func (s) TestTLS_DisabledALPNClient(t *testing.T) {
	initialVal := envconfig.EnforceALPNEnabled
	defer func() {
		envconfig.EnforceALPNEnabled = initialVal
	}()

	tests := []struct {
		name         string
		alpnEnforced bool
		wantErr      bool
	}{
		{
			name:         "enforced",
			alpnEnforced: true,
			wantErr:      true,
		},
		{
			name: "not_enforced",
		},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			envconfig.EnforceALPNEnabled = tc.alpnEnforced

			listener, err := tls.Listen("tcp", "localhost:0", &tls.Config{
				Certificates: []tls.Certificate{serverCert},
				NextProtos:   []string{}, // Empty list indicates ALPN is disabled.
			})
			if err != nil {
				t.Fatalf("Error starting TLS server: %v", err)
			}

			errCh := make(chan error, 1)
			go func() {
				conn, err := listener.Accept()
				if err != nil {
					errCh <- fmt.Errorf("listener.Accept returned error: %v", err)
				} else {
					// The first write to the TLS listener initiates the TLS handshake.
					conn.Write([]byte("Hello, World!"))
					conn.Close()
				}
				close(errCh)
			}()

			serverAddr := listener.Addr().String()
			conn, err := net.Dial("tcp", serverAddr)
			if err != nil {
				t.Fatalf("net.Dial(%s) failed: %v", serverAddr, err)
			}
			defer conn.Close()

			ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
			defer cancel()

			clientCfg := tls.Config{
				ServerName: serverName,