I have a struct
type Server struct {
grpcServerPort int
grpcServer *grpc.Server
writer *kafka.Writer
}
this Server has lot of methods including -
func NewServer(port int) *Server {
server := &Server{
grpcServerPort: port,
}
gs := grpc.NewServer()
server.grpcServer = gs
return server
}
func (s *Server) StartServer() {
createKafkaTopic("brokker_url", "my_topic")
s.writer = &kafka.Writer{
Addr: kafka.TCP("urls"),
Topic: "my_topic",
Balancer: &kafka.Hash{},
MaxAttempts: 1,
BatchSize: 1,
}
listener, err := net.Listen("tcp", fmt.Sprintf(":%d", s.grpcServerPort))
if err != nil {
fmt.Printf("failed to listen: %v", err)
}
go s.grpcServer.Serve(listener)
}
func (s *Server) produceEvents(key string, val string) error {
msg := kafka.Message{
Key: []byte(key),
Value: []byte(val),
}
err = s.writer.WriteMessages(context.Background(), msg)
if err != nil {
return err
}
return nil
}
Now createTopic method panic if no kafka broker is up and running at my machine. I want to know how to mock createTopic and produceEvents so that I can write unit test case for other methods of server.
CodePudding user response:
I just met your case last week. And this is how I resolve that:
type KafkaWriter interface {
Method001fKafkaWriter()
Method002fKafkaWriter()
}
type Server struct {
grpcServerPort int
grpcServer *grpc.Server
writer KafkaWriter
}
Now, you can mock Kafka dependencies with the interface
type mockKafkaWriter struct {
}
func (*mockKafkaWriter) Method001fKafkaWriter() {}
func (*mockKafkaWriter) Method002fKafkaWriter() {}
I hope this can help you!
CodePudding user response:
you can define an interface and then define a mock struct to implement it, now you can test it.
type Server struct {
grpcServerPort int
grpcServer *grpc.Server
writer KafkaWriterWrapper
}
type KafkaWriterWrapper interface {
Write(msg string) error // Suppose kafka.Writer has func Write(msg string) error
}
type KafkaWriterWrapperImpl struct {
*kafka.Writer
}
type MockKafkaWriterWrapperImpl struct {
}
func (m *MockKafkaWriterWrapperImpl) Write(msg string) error {
// logic
return nil
}