Wanted but not invoked:Mockito

Question

I am trying to test below Vote.java which has a method called isEligibleToVote() which in turn calls another method getResult() after a check. I am trying to capture the argument and assert but while doing so I am getting Wanted but not invoked: vote.getResult(<Capturing argument>);

I understand this is because of vote.isEligibleToVote(18); as I have declared vote using @Mock which is incorrect, but I don't know how can I test this class using ArgumentCaptor and verify methods.

Vote.java

public class Vote {
public void isEligibleToVote(int age){
    if(age>18)
        getResult("yes");
    else
        getResult("no");

}

public String getResult(String result){
    return result;
}

}

VoteTest.java

@ExtendWith(MockitoExtension.class)
public class VoteTest {

    @Mock
    Vote vote;

    @Test
    public void isEligibleToVote_test(){
        ArgumentCaptor<String> stringArgumentCaptor = ArgumentCaptor.forClass(String.class);
        vote.isEligibleToVote(18);
        verify(vote).getResult(stringArgumentCaptor.capture());
        assertEquals("yes", stringArgumentCaptor.getValue());
    }
}

Error Staacktrace

    Wanted but not invoked:
vote.getResult(<Capturing argument>);
-> at VoteTest.isEligibleToVote_test(VoteTest.java:24)

However, there was exactly 1 interaction with this mock:
vote.isEligibletoVote(18);
-> at VoteTest.isEligibleToVote_test(VoteTest.java:23)


Wanted but not invoked:
vote.getResult(<Capturing argument>);
-> at VoteTest.isEligibleToVote_test(VoteTest.java:24)

However, there was exactly 1 interaction with this mock:
vote.isEligibletoVote(18);
-> at VoteTest.isEligibleToVote_test(VoteTest.java:23)


    at VoteTest.isEligibleToVote_test(VoteTest.java:24)

I understand vote is mock, but I want to know how can I call vote.iseligibleTovote(18) and get the arguments of getResult from inside if and else condition

Answer 1

Use @Spy instead of @Mock to do the verification. You must call when() on any methods of a mocked object which you aren't doing hence the wanted but not invoked

Answer 2

TLDR: Use @Spy insted of @Mock

@Mock is used when you want to mock an object and insert it into another object.
@Spy is used when you want to look at the intermediate values. In your case getResult()

Use the below code for better understanding:

@RunWith(MockitoJUnitRunner.class)
public class VoteTest {

    @Spy
    Vote vote;

    @Test
    public void isEligibleToVote_test(){
        ArgumentCaptor<String> stringArgumentCaptor = ArgumentCaptor.forClass(String.class);
        vote.isEligibleToVote(19);
        verify(vote).getResult(stringArgumentCaptor.capture());
        assertEquals("yes", stringArgumentCaptor.getValue());
   }
}

Answer 3

your vote is a mock you can't call method on him.

look at when when(vote.isEligibleToVote(18)).thenReturn("WHat you want")

edit : look at https://www.baeldung.com/mockito-behavior