diff --git a/interop/client/client.go b/interop/client/client.go
index bcf8e64e..b8a345ca 100644
--- a/interop/client/client.go
+++ b/interop/client/client.go
@@ -191,7 +191,7 @@ func main() {
 		interop.DoCustomMetadata(tc)
 		grpclog.Println("CustomMetadata done")
 	case "unimplemented_method":
-		interop.DoUnimplementedMethod(tc)
+		interop.DoUnimplementedMethod(serverAddr)
 		grpclog.Println("UnimplementedMethod done")
 	case "unimplemented_service":
 		interop.DoUnimplementedService(testpb.NewUnimplementedServiceClient(conn))
diff --git a/interop/grpc_testing/test.pb.go b/interop/grpc_testing/test.pb.go
index 778ef6ef..e8c425ba 100755
--- a/interop/grpc_testing/test.pb.go
+++ b/interop/grpc_testing/test.pb.go
@@ -432,9 +432,6 @@ type TestServiceClient interface {
 	// stream of responses are returned to the client when the server starts with
 	// first request.
 	HalfDuplexCall(ctx context.Context, opts ...grpc.CallOption) (TestService_HalfDuplexCallClient, error)
-	// The test server will not implement this method. It will be used
-	// to test the behavior when clients call unimplemented methods.
-	UnimplementedCall(ctx context.Context, in *Empty, opts ...grpc.CallOption) (*Empty, error)
 }
 
 type testServiceClient struct {
@@ -591,15 +588,6 @@ func (x *testServiceHalfDuplexCallClient) Recv() (*StreamingOutputCallResponse,
 	return m, nil
 }
 
-func (c *testServiceClient) UnimplementedCall(ctx context.Context, in *Empty, opts ...grpc.CallOption) (*Empty, error) {
-	out := new(Empty)
-	err := grpc.Invoke(ctx, "/grpc.testing.TestService/UnimplementedCall", in, out, c.cc, opts...)
-	if err != nil {
-		return nil, err
-	}
-	return out, nil
-}
-
 // Server API for TestService service
 
 type TestServiceServer interface {
@@ -623,9 +611,6 @@ type TestServiceServer interface {
 	// stream of responses are returned to the client when the server starts with
 	// first request.
 	HalfDuplexCall(TestService_HalfDuplexCallServer) error
-	// The test server will not implement this method. It will be used
-	// to test the behavior when clients call unimplemented methods.
-	UnimplementedCall(context.Context, *Empty) (*Empty, error)
 }
 
 func RegisterTestServiceServer(s *grpc.Server, srv TestServiceServer) {
@@ -767,24 +752,6 @@ func (x *testServiceHalfDuplexCallServer) Recv() (*StreamingOutputCallRequest, e
 	return m, nil
 }
 
-func _TestService_UnimplementedCall_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
-	in := new(Empty)
-	if err := dec(in); err != nil {
-		return nil, err
-	}
-	if interceptor == nil {
-		return srv.(TestServiceServer).UnimplementedCall(ctx, in)
-	}
-	info := &grpc.UnaryServerInfo{
-		Server:     srv,
-		FullMethod: "/grpc.testing.TestService/UnimplementedCall",
-	}
-	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
-		return srv.(TestServiceServer).UnimplementedCall(ctx, req.(*Empty))
-	}
-	return interceptor(ctx, in, info, handler)
-}
-
 var _TestService_serviceDesc = grpc.ServiceDesc{
 	ServiceName: "grpc.testing.TestService",
 	HandlerType: (*TestServiceServer)(nil),
@@ -797,10 +764,6 @@ var _TestService_serviceDesc = grpc.ServiceDesc{
 			MethodName: "UnaryCall",
 			Handler:    _TestService_UnaryCall_Handler,
 		},
-		{
-			MethodName: "UnimplementedCall",
-			Handler:    _TestService_UnimplementedCall_Handler,
-		},
 	},
 	Streams: []grpc.StreamDesc{
 		{
@@ -898,46 +861,46 @@ var _UnimplementedService_serviceDesc = grpc.ServiceDesc{
 func init() { proto.RegisterFile("test.proto", fileDescriptor0) }
 
 var fileDescriptor0 = []byte{
-	// 654 bytes of a gzipped FileDescriptorProto
-	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x09, 0x6e, 0x88, 0x02, 0xff, 0xbc, 0x54, 0x4f, 0x6f, 0xd3, 0x4e,
-	0x10, 0xfd, 0x39, 0x4d, 0x7e, 0x69, 0x27, 0xa9, 0x09, 0x53, 0x2a, 0xdc, 0x14, 0x89, 0xc8, 0x1c,
-	0x30, 0x48, 0x04, 0x14, 0x09, 0x0e, 0x48, 0x80, 0x4a, 0x9b, 0x8a, 0x4a, 0x6d, 0x53, 0xec, 0xe6,
-	0x1c, 0x2d, 0xc9, 0xd4, 0xb5, 0xe4, 0x7f, 0xd8, 0xeb, 0x8a, 0xf4, 0xc0, 0x97, 0xe1, 0x43, 0xf0,
-	0xdd, 0x38, 0xa1, 0x5d, 0xdb, 0x89, 0x93, 0xa6, 0xa2, 0xa1, 0xc0, 0x6d, 0x77, 0xf6, 0xcd, 0x9b,
-	0x79, 0x33, 0xcf, 0x06, 0xe0, 0x14, 0xf3, 0x76, 0x18, 0x05, 0x3c, 0xc0, 0xba, 0x1d, 0x85, 0xc3,
-	0xb6, 0x08, 0x38, 0xbe, 0xad, 0x57, 0xa1, 0xd2, 0xf5, 0x42, 0x3e, 0xd6, 0x0f, 0xa1, 0x7a, 0xc2,
-	0xc6, 0x6e, 0xc0, 0x46, 0xf8, 0x0c, 0xca, 0x7c, 0x1c, 0x92, 0xa6, 0xb4, 0x14, 0x43, 0xed, 0x6c,
-	0xb5, 0x8b, 0x09, 0xed, 0x0c, 0x74, 0x3a, 0x0e, 0xc9, 0x94, 0x30, 0x44, 0x28, 0x7f, 0x0a, 0x46,
-	0x63, 0xad, 0xd4, 0x52, 0x8c, 0xba, 0x29, 0xcf, 0xfa, 0x6b, 0x80, 0xee, 0xf0, 0x3c, 0xb0, 0x38,
-	0xe3, 0x49, 0x2c, 0x10, 0xc3, 0x60, 0x94, 0x12, 0x56, 0x4c, 0x79, 0x46, 0x0d, 0xaa, 0x1e, 0xc5,
-	0x31, 0xb3, 0x49, 0x26, 0xae, 0x99, 0xf9, 0x55, 0xff, 0x5e, 0x82, 0x75, 0xcb, 0xf1, 0x42, 0x97,
-	0x4c, 0xfa, 0x9c, 0x50, 0xcc, 0xf1, 0x2d, 0xac, 0x47, 0x14, 0x87, 0x81, 0x1f, 0xd3, 0xe0, 0x66,
-	0x9d, 0xd5, 0x73, 0xbc, 0xb8, 0xe1, 0xa3, 0x42, 0x7e, 0xec, 0x5c, 0xa6, 0x15, 0x2b, 0x53, 0x90,
-	0xe5, 0x5c, 0x12, 0x3e, 0x87, 0x6a, 0x98, 0x32, 0x68, 0x2b, 0x2d, 0xc5, 0xa8, 0x75, 0x36, 0x17,
-	0xd2, 0x9b, 0x39, 0x4a, 0xb0, 0x9e, 0x39, 0xae, 0x3b, 0x48, 0x62, 0x8a, 0x7c, 0xe6, 0x91, 0x56,
-	0x6e, 0x29, 0xc6, 0xaa, 0x59, 0x17, 0xc1, 0x7e, 0x16, 0x43, 0x03, 0x1a, 0x12, 0x14, 0xb0, 0x84,
-	0x9f, 0x0f, 0xe2, 0x61, 0x10, 0x92, 0x56, 0x91, 0x38, 0x55, 0xc4, 0x7b, 0x22, 0x6c, 0x89, 0x28,
-	0xee, 0xc0, 0x9d, 0x69, 0x93, 0x72, 0x6e, 0x5a, 0x55, 0xf6, 0xa1, 0xcd, 0xf6, 0x31, 0x9d, 0xab,
-	0xa9, 0x4e, 0x04, 0xc8, 0xbb, 0xfe, 0x15, 0xd4, 0x7c, 0x70, 0x69, 0xbc, 0x28, 0x4a, 0xb9, 0x91,
-	0xa8, 0x26, 0xac, 0x4e, 0xf4, 0xa4, 0x7b, 0x99, 0xdc, 0xf1, 0x21, 0xd4, 0x8a, 0x32, 0x56, 0xe4,
-	0x33, 0x04, 0x13, 0x09, 0xfa, 0x21, 0x6c, 0x59, 0x3c, 0x22, 0xe6, 0x39, 0xbe, 0x7d, 0xe0, 0x87,
-	0x09, 0xdf, 0x65, 0xae, 0x9b, 0x2f, 0x71, 0xd9, 0x56, 0xf4, 0x53, 0x68, 0x2e, 0x62, 0xcb, 0x94,
-	0xbd, 0x82, 0xfb, 0xcc, 0xb6, 0x23, 0xb2, 0x19, 0xa7, 0xd1, 0x20, 0xcb, 0x49, 0xb7, 0x9b, 0xda,
-	0x6c, 0x73, 0xfa, 0x9c, 0x51, 0x8b, 0x35, 0xeb, 0x07, 0x80, 0x39, 0xc7, 0x09, 0x8b, 0x98, 0x47,
-	0x9c, 0x22, 0xe9, 0xd0, 0x42, 0xaa, 0x3c, 0x0b, 0xb9, 0x8e, 0xcf, 0x29, 0xba, 0x60, 0x62, 0xc7,
-	0x99, 0x67, 0x20, 0x0f, 0xf5, 0x63, 0xfd, 0x5b, 0xa9, 0xd0, 0x61, 0x2f, 0xe1, 0x73, 0x82, 0x6f,
-	0xeb, 0xda, 0x8f, 0xb0, 0x31, 0xc9, 0x0f, 0x27, 0xad, 0x6a, 0xa5, 0xd6, 0x8a, 0x51, 0xeb, 0xb4,
-	0x66, 0x59, 0xae, 0x4a, 0x32, 0x31, 0xba, 0x2a, 0x73, 0x69, 0x8f, 0xff, 0x01, 0x53, 0x1e, 0xc3,
-	0xf6, 0xc2, 0x21, 0xfd, 0xa6, 0x43, 0x9f, 0xbe, 0x83, 0x5a, 0x61, 0x66, 0xd8, 0x80, 0xfa, 0x6e,
-	0xef, 0xe8, 0xc4, 0xec, 0x5a, 0xd6, 0xce, 0xfb, 0xc3, 0x6e, 0xe3, 0x3f, 0x44, 0x50, 0xfb, 0xc7,
-	0x33, 0x31, 0x05, 0x01, 0xfe, 0x37, 0x77, 0x8e, 0xf7, 0x7a, 0x47, 0x8d, 0x52, 0xe7, 0x47, 0x19,
-	0x6a, 0xa7, 0x14, 0x73, 0x8b, 0xa2, 0x0b, 0x67, 0x48, 0xf8, 0x12, 0xd6, 0xe4, 0x2f, 0x50, 0xb4,
-	0x85, 0x1b, 0x73, 0xba, 0xc4, 0x43, 0x73, 0x51, 0x10, 0xf7, 0x61, 0xad, 0xef, 0xb3, 0x28, 0x4d,
-	0xdb, 0x9e, 0x45, 0xcc, 0xfc, 0xbe, 0x9a, 0x0f, 0x16, 0x3f, 0x66, 0x03, 0x70, 0x61, 0x63, 0xc1,
-	0x7c, 0xd0, 0x98, 0x4b, 0xba, 0xd6, 0x67, 0xcd, 0x27, 0x37, 0x40, 0xa6, 0xb5, 0x5e, 0x28, 0xe8,
-	0x00, 0x5e, 0xfd, 0xa8, 0xf0, 0xf1, 0x35, 0x14, 0xf3, 0x1f, 0x71, 0xd3, 0xf8, 0x35, 0x30, 0x2d,
-	0x65, 0x88, 0x52, 0xea, 0x7e, 0xe2, 0xba, 0x7b, 0x49, 0xe8, 0xd2, 0x97, 0xbf, 0xa6, 0xc9, 0x50,
-	0xa4, 0x2a, 0xf5, 0x03, 0x73, 0xcf, 0xfe, 0x45, 0xa9, 0x37, 0x70, 0xb7, 0xef, 0xcb, 0x0d, 0x7a,
-	0xe4, 0x73, 0x1a, 0x2d, 0xe7, 0x9a, 0x4e, 0x1f, 0xee, 0xcd, 0xa4, 0xe7, 0x26, 0xbc, 0x1d, 0xed,
-	0xcf, 0x00, 0x00, 0x00, 0xff, 0xff, 0x93, 0xfa, 0x94, 0xe8, 0xe1, 0x07, 0x00, 0x00,
+	// 649 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x09, 0x6e, 0x88, 0x02, 0xff, 0xbc, 0x54, 0x4d, 0x6f, 0xd3, 0x40,
+	0x10, 0xc5, 0x69, 0x42, 0xda, 0x49, 0x6a, 0xc2, 0x94, 0x0a, 0x37, 0x45, 0x22, 0x32, 0x07, 0x0c,
+	0x12, 0x01, 0x45, 0x82, 0x03, 0x12, 0xa0, 0xd2, 0xa6, 0xa2, 0x52, 0xdb, 0x14, 0xbb, 0x39, 0x47,
+	0x4b, 0x32, 0x75, 0x2d, 0xf9, 0x0b, 0x7b, 0x5d, 0x91, 0x1e, 0xf8, 0x33, 0xfc, 0x08, 0x0e, 0xfc,
+	0x39, 0xb4, 0x6b, 0x3b, 0x71, 0xd2, 0x54, 0x34, 0x7c, 0xdd, 0x76, 0xdf, 0xbe, 0xf9, 0x78, 0x33,
+	0xcf, 0x06, 0xe0, 0x14, 0xf3, 0x76, 0x18, 0x05, 0x3c, 0xc0, 0xba, 0x1d, 0x85, 0xc3, 0xb6, 0x00,
+	0x1c, 0xdf, 0xd6, 0xab, 0x50, 0xe9, 0x7a, 0x21, 0x1f, 0xeb, 0x87, 0x50, 0x3d, 0x61, 0x63, 0x37,
+	0x60, 0x23, 0x7c, 0x06, 0x65, 0x3e, 0x0e, 0x49, 0x53, 0x5a, 0x8a, 0xa1, 0x76, 0xb6, 0xda, 0xc5,
+	0x80, 0x76, 0x46, 0x3a, 0x1d, 0x87, 0x64, 0x4a, 0x1a, 0x22, 0x94, 0x3f, 0x05, 0xa3, 0xb1, 0x56,
+	0x6a, 0x29, 0x46, 0xdd, 0x94, 0x67, 0xfd, 0x35, 0x40, 0x77, 0x78, 0x1e, 0x58, 0x9c, 0xf1, 0x24,
+	0x16, 0x8c, 0x61, 0x30, 0x4a, 0x13, 0x56, 0x4c, 0x79, 0x46, 0x0d, 0xaa, 0x1e, 0xc5, 0x31, 0xb3,
+	0x49, 0x06, 0xae, 0x99, 0xf9, 0x55, 0xff, 0x5e, 0x82, 0x75, 0xcb, 0xf1, 0x42, 0x97, 0x4c, 0xfa,
+	0x9c, 0x50, 0xcc, 0xf1, 0x2d, 0xac, 0x47, 0x14, 0x87, 0x81, 0x1f, 0xd3, 0xe0, 0x66, 0x9d, 0xd5,
+	0x73, 0xbe, 0xb8, 0xe1, 0xa3, 0x42, 0x7c, 0xec, 0x5c, 0xa6, 0x15, 0x2b, 0x53, 0x92, 0xe5, 0x5c,
+	0x12, 0x3e, 0x87, 0x6a, 0x98, 0x66, 0xd0, 0x56, 0x5a, 0x8a, 0x51, 0xeb, 0x6c, 0x2e, 0x4c, 0x6f,
+	0xe6, 0x2c, 0x91, 0xf5, 0xcc, 0x71, 0xdd, 0x41, 0x12, 0x53, 0xe4, 0x33, 0x8f, 0xb4, 0x72, 0x4b,
+	0x31, 0x56, 0xcd, 0xba, 0x00, 0xfb, 0x19, 0x86, 0x06, 0x34, 0x24, 0x29, 0x60, 0x09, 0x3f, 0x1f,
+	0xc4, 0xc3, 0x20, 0x24, 0xad, 0x22, 0x79, 0xaa, 0xc0, 0x7b, 0x02, 0xb6, 0x04, 0x8a, 0x3b, 0x70,
+	0x67, 0xda, 0xa4, 0x9c, 0x9b, 0x56, 0x95, 0x7d, 0x68, 0xb3, 0x7d, 0x4c, 0xe7, 0x6a, 0xaa, 0x13,
+	0x01, 0xf2, 0xae, 0x7f, 0x05, 0x35, 0x1f, 0x5c, 0x8a, 0x17, 0x45, 0x29, 0x37, 0x12, 0xd5, 0x84,
+	0xd5, 0x89, 0x9e, 0x74, 0x2f, 0x93, 0x3b, 0x3e, 0x84, 0x5a, 0x51, 0xc6, 0x8a, 0x7c, 0x86, 0x60,
+	0x22, 0x41, 0x3f, 0x84, 0x2d, 0x8b, 0x47, 0xc4, 0x3c, 0xc7, 0xb7, 0x0f, 0xfc, 0x30, 0xe1, 0xbb,
+	0xcc, 0x75, 0xf3, 0x25, 0x2e, 0xdb, 0x8a, 0x7e, 0x0a, 0xcd, 0x45, 0xd9, 0x32, 0x65, 0xaf, 0xe0,
+	0x3e, 0xb3, 0xed, 0x88, 0x6c, 0xc6, 0x69, 0x34, 0xc8, 0x62, 0xd2, 0xed, 0xa6, 0x36, 0xdb, 0x9c,
+	0x3e, 0x67, 0xa9, 0xc5, 0x9a, 0xf5, 0x03, 0xc0, 0x3c, 0xc7, 0x09, 0x8b, 0x98, 0x47, 0x9c, 0x22,
+	0xe9, 0xd0, 0x42, 0xa8, 0x3c, 0x0b, 0xb9, 0x8e, 0xcf, 0x29, 0xba, 0x60, 0x62, 0xc7, 0x99, 0x67,
+	0x20, 0x87, 0xfa, 0xb1, 0xfe, 0xad, 0x54, 0xe8, 0xb0, 0x97, 0xf0, 0x39, 0xc1, 0x7f, 0xea, 0xda,
+	0x8f, 0xb0, 0x31, 0x89, 0x0f, 0x27, 0xad, 0x6a, 0xa5, 0xd6, 0x8a, 0x51, 0xeb, 0xb4, 0x66, 0xb3,
+	0x5c, 0x95, 0x64, 0x62, 0x74, 0x55, 0xe6, 0xd2, 0x1e, 0xff, 0x0b, 0xa6, 0x3c, 0x86, 0xed, 0x85,
+	0x43, 0xfa, 0x4d, 0x87, 0x3e, 0x7d, 0x07, 0xb5, 0xc2, 0xcc, 0xb0, 0x01, 0xf5, 0xdd, 0xde, 0xd1,
+	0x89, 0xd9, 0xb5, 0xac, 0x9d, 0xf7, 0x87, 0xdd, 0xc6, 0x2d, 0x44, 0x50, 0xfb, 0xc7, 0x33, 0x98,
+	0x82, 0x00, 0xb7, 0xcd, 0x9d, 0xe3, 0xbd, 0xde, 0x51, 0xa3, 0xd4, 0xf9, 0x51, 0x86, 0xda, 0x29,
+	0xc5, 0xdc, 0xa2, 0xe8, 0xc2, 0x19, 0x12, 0xbe, 0x84, 0x35, 0xf9, 0x0b, 0x14, 0x6d, 0xe1, 0xc6,
+	0x9c, 0x2e, 0xf1, 0xd0, 0x5c, 0x04, 0xe2, 0x3e, 0xac, 0xf5, 0x7d, 0x16, 0xa5, 0x61, 0xdb, 0xb3,
+	0x8c, 0x99, 0xdf, 0x57, 0xf3, 0xc1, 0xe2, 0xc7, 0x6c, 0x00, 0x2e, 0x6c, 0x2c, 0x98, 0x0f, 0x1a,
+	0x73, 0x41, 0xd7, 0xfa, 0xac, 0xf9, 0xe4, 0x06, 0xcc, 0xb4, 0xd6, 0x0b, 0x05, 0x1d, 0xc0, 0xab,
+	0x1f, 0x15, 0x3e, 0xbe, 0x26, 0xc5, 0xfc, 0x47, 0xdc, 0x34, 0x7e, 0x4d, 0x4c, 0x4b, 0x19, 0xa2,
+	0x94, 0xba, 0x9f, 0xb8, 0xee, 0x5e, 0x12, 0xba, 0xf4, 0xe5, 0x9f, 0x69, 0x32, 0x14, 0xa9, 0x4a,
+	0xfd, 0xc0, 0xdc, 0xb3, 0xff, 0x50, 0xaa, 0xd3, 0x87, 0x7b, 0x7d, 0x5f, 0x6e, 0xd0, 0x23, 0x9f,
+	0xd3, 0x28, 0x77, 0xd1, 0x1b, 0xb8, 0x3b, 0x83, 0x2f, 0xe7, 0xa6, 0x9f, 0x01, 0x00, 0x00, 0xff,
+	0xff, 0xdd, 0xb5, 0x50, 0x6f, 0xa2, 0x07, 0x00, 0x00,
 }
diff --git a/interop/grpc_testing/test.proto b/interop/grpc_testing/test.proto
index e8e41638..cc2bb74f 100644
--- a/interop/grpc_testing/test.proto
+++ b/interop/grpc_testing/test.proto
@@ -150,10 +150,6 @@ service TestService {
   // first request.
   rpc HalfDuplexCall(stream StreamingOutputCallRequest)
       returns (stream StreamingOutputCallResponse);
-
-  // The test server will not implement this method. It will be used
-  // to test the behavior when clients call unimplemented methods.
-  rpc UnimplementedCall(grpc.testing.Empty) returns (grpc.testing.Empty);
 }
 
 // A simple service NOT implemented at servers so clients can test for
diff --git a/interop/test_utils.go b/interop/test_utils.go
index 75082161..0a716fb4 100644
--- a/interop/test_utils.go
+++ b/interop/test_utils.go
@@ -52,11 +52,11 @@ import (
 )
 
 var (
-	reqSizes      = []int{27182, 8, 1828, 45904}
-	respSizes     = []int{31415, 9, 2653, 58979}
-	largeReqSize  = 271828
-	largeRespSize = 314159
-	initialMetadataKey = "x-grpc-test-echo-initial"
+	reqSizes            = []int{27182, 8, 1828, 45904}
+	respSizes           = []int{31415, 9, 2653, 58979}
+	largeReqSize        = 271828
+	largeRespSize       = 314159
+	initialMetadataKey  = "x-grpc-test-echo-initial"
 	trailingMetadataKey = "x-grpc-test-echo-trailing-bin"
 )
 
@@ -457,9 +457,9 @@ func DoCancelAfterFirstResponse(tc testpb.TestServiceClient) {
 }
 
 var (
-	initialMetadataValue = "test_initial_metadata_value"
+	initialMetadataValue  = "test_initial_metadata_value"
 	trailingMetadataValue = "\x0a\x0b\x0a\x0b\x0a\x0b"
-	customMetadata = metadata.Pairs(
+	customMetadata        = metadata.Pairs(
 		initialMetadataKey, initialMetadataValue,
 		trailingMetadataKey, trailingMetadataValue,
 	)
@@ -489,7 +489,7 @@ func DoCustomMetadata(tc testpb.TestServiceClient) {
 		ResponseSize: proto.Int32(int32(1)),
 		Payload:      pl,
 	}
-	ctx := metadata.NewContext(context.Background(), customMetadata);
+	ctx := metadata.NewContext(context.Background(), customMetadata)
 	var header, trailer metadata.MD
 	reply, err := tc.UnaryCall(
 		ctx,
@@ -586,12 +586,16 @@ func DoUnimplementedService(tc testpb.UnimplementedServiceClient) {
 	}
 }
 
-func DoUnimplementedMethod(tc testpb.TestServiceClient) {
-	var code int32 = 12
-	expectedCode := codes.Code(code)
-	_, err := tc.UnimplementedCall(context.Background(), &testpb.Empty{})
-	if grpc.Code(err) != expectedCode {
-		grpclog.Fatalf("%v.UnimplementedCall() = _, %v, want _, %v", tc, grpc.Code(err), expectedCode)
+func DoUnimplementedMethod(serverAddr string) {
+	cc, err := grpc.Dial(serverAddr, grpc.WithInsecure(), grpc.WithBlock())
+	if err != nil {
+		grpclog.Fatalf("Failed to dial to the backend %v", err)
+	}
+	var (
+		req, reply proto.Message
+	)
+	if err := grpc.Invoke(context.Background(), "/foo/bar", req, reply, cc); err == nil || grpc.Code(err) != codes.Unimplemented {
+		grpclog.Fatalf("grpc.Invoke(_, _, _, _, _) = %v, want error code %s", err, codes.Unimplemented)
 	}
 }
 
@@ -603,10 +607,6 @@ func NewTestServer() testpb.TestServiceServer {
 	return &testServer{}
 }
 
-func (s *testServer) UnimplementedCall(ctx context.Context, in *testpb.Empty) (*testpb.Empty, error) {
-	return nil, grpc.Errorf(codes.Code(12), "")  // 12 == UNIMPLEMENTED
-}
-
 func (s *testServer) EmptyCall(ctx context.Context, in *testpb.Empty) (*testpb.Empty, error) {
 	return new(testpb.Empty), nil
 }