测试使用Mockito重复代码

Question

My tests just repeats the code. For method

public void start(Context context) {
    context.setA(CONST_A);
    context.setB(CONST_B);
    ...
}

I wrote test using Mockito

@Test
public void testStart() throws Exception {
    Context mockContext = mock(Context.class);

    action.start(mockContext);

    verify(mockAction).setA(Action.CONST_A);
    verify(mockAction).setB(Action.CONST_B);
    ...
}

Or for

public void act() {
   state.act();
}

test

@Test
public void testAct() throws Exception {
    State mockState = mock(State.class);
    context.setState(mockState);

    context.act();

    verify(mockState).act();
}

Are such tests useful? Such methods need to be tested and how to test them?

Answer 1

In my opinion, you should not try to have a 100% test coverage in general. Having a high test coverage is good, having a perfect coverage is useless and wastes your time. Any method that just sets, gets or delegate work to another method should not be tested, because it will cost you much to write and even more when refactoring. Finally, it won't add more anti-regression value or any help for anyone using your API.

Prefer testing method with real intelligence, risky or sensitive. The cases you submitted are test more Mockito than your own code. This will take build time and won't help you.

Answer 2

Personally I don't consider verify() useful at all since it directly tests the implementation instead of the result of your method. This will give you false failures when you change the implementation while the result is still correct.

As to whether this is useful: there is no logic to test so no, it's not particularly useful.

Answer 3

According to the comments I left in other answers

public void start(Context context) {
  context.setA(CONST_A);
  context.setB(CONST_B);
  ...
}

should not be tested with Mockito, rather

@Test
public void testStart() throws Exception {
   Context context = new Context();

   action.start(context);

   assertThat(context.getA(), equalTo(Action.CONST_A));
   assertThat(context.getB(), equalTo(Action.CONST_B));
}

Its not much different, but in comparison with verify it can also get true, if start manages to reach this state without calling a setter or getter.