如何在Go中测试通话期望

Question

I have a class MyClass that I want to test.

MyClass has a void method that calls an inner server to do something.

func (d *MyClass) SendToServer(args)
  do stuff....
  server.Send(myMessage)

I want to mock the server call Send, but since the method is a void method I can't be sure that I am actually calling it right.

These are the options I had in mind:

1. Use gomock, mock the server, and set expectations on the send method of the service
2. create my own MockServer, and "override" the method Send with a bunch of verifications. Something like:

func (d *MockedServer) Send(message) // verify message...

1. create my own MockServer, but instead of verifying the expectation within the method, add the message to a list of messages, and then verify the content of the list.

What is a better approach in Go?

Answer 1

You could make a function out of your method like this:

var sendToServer = (*Server).Send

func func (d *MyClass) SendToServer(args) {
    // ...
    sendToServer(server, msg)
    // ...
}

And in your tests:

func TestMyClass_SendToServer(t *testing.T) {
    // ...
    sent := false
    sendToServer = func(*Server, args) {
        sent = true
    }
    mc.SendToServer(args)
    if !sent {
        t.Error("fail")
    }
}

This is described in Andrew Gerrand's Testing Techniques talk.