mockito - negativeTest for applicationEventPublisher

[Rakshan]

I have a runner which produces an event when the value is updated/changed.


[CODE lang="java" title="runner"]public void run(){

if(val!= cachedValue){
applicationEventPublisher.publishEvent(new DataEvent(this, val);
//only if a new value comes, then the event is fired
}

}[/CODE]


To verify I have a testcase, where the functionality is called twice with same inputs(For eg: When called for the first time, the value is not equal to cached value, hence event is fired. But when called again, I expect the event to not get fired)

Mockito Junit test:

public class Testing{

public UnderTest underTest;

@mockbean
ApplicationEventPublisher applicationEventPublisher;
@Captor
private ArgumentCaptor<DataEvent> eventArgumentCaptor,eventArgumentCaptor2;
@Test
public test1(){

        // some sample inputs

        underTest.run() // first run, i expect the event to fire
        verify(applicationEventPublisher).publishEvent(eventArgumentCaptor.capture()); // i get the value as expected here


        //now i run again
        underTest.run();
        verify(applicationEventPublisher, never()).publishEvent(eventArgumentCaptor2.capture());
        //fails here, the result show that the event is fired
        assertEquals(0, eventArgumentCaptor2.getAllValues().size());
    }

}

I am not understanding what is going wrong after the second run here. I expect to see no events(which is the case while debugging the runner), but does not work.

Any suggestions or inputs here please? ALso excuse my language, still learning Deutsch

 

[LimDul]

The problem ist, verfiy doesn't check if if was called since the last time you called verify.
So a check for never will fail, because it was called. You should check in both verify checks for times(1) do ensure the number of calls hasn't gone up.

 

[Rakshan]

{
    underTest.run();
    verify(applicationEventPublisher,times(1)).publishEvent(eventArgumentCaptor.capture());
    //called twice
    underTest.run();   
 //   verifyNoMoreInteractions(applicationEventPublisher);   
    verify(applicationEventPublisher, times(1)).publishEvent(eventArgumentCaptor2.capture());   
    assertEquals(0, eventArgumentCaptor2.getAllValues().size());
    
}

But the assert statement fails here. Expected = 0, Actual =1

 

[LimDul]

Because you expect one Argument - from the first call. What check with line 7 and 8 is not the result of line 5. It is the result of line 2 and 5 combined. And then there is one call to publishEvent and that argument is what you get.

 

[Rakshan]

Inspite of using the separate ArgumentCaptor after the second underTest.run(); ? I expect it to capture that there has been no event ..
Anyways could you suggest some idea to overcome this?

 

[LimDul]

You could try Mockito.reset after the first verify. That should sovle your problems I think (I have never used it, so no guarantee)