How do you validate the call of the same simulation method using the same parameters that change the state between calls in mockito?

I have the following code for unit testing:

public void foo() {
    Entity entity = //...
    persistence.save(entity);
    entity.setDate(new Date());
    persistence.save(entity);
}

I want to verify the first call to persistence When saving, entity Getdate() returns null

Therefore, I can't use mockito Verify (/ *... * /), because the method foo has completed and entity is called setDate(Date).

So I think I need to validate the call when it occurs How do I do this with mockito?

Solution

I created the following answer implementation:

public class CapturingAnswer<T,R> implements Answer<T> {

    private final Function<InvocationOnMock,R> capturingFunction;

    private final List<R> capturedValues = new ArrayList<R>();

    public CapturingAnswer(final Function<InvocationOnMock,R> capturingFunction) {
        super();
        this.capturingFunction = capturingFunction;
    }

    @Override
    public T answer(final InvocationOnMock invocation) throws Throwable {
        capturedValues.add(capturingFunction.apply(invocation));
        return null;
    }

    public List<R> getCapturedValues() {
        return Collections.unmodifiableList(capturedValues);
    }

}

This answer captures the properties of the call in progress The captured values can be used for simple assertions This implementation uses the Java 8 API If this is not available, you need to use an interface that can convert invocationonmock to a captured value The usage in the test case is as follows:

@Test
public void testSomething() {
    CapturingAnswer<Void,Date> captureDates = new CapturingAnswer<>(this::getEntityDate)
    Mockito.doAnswer(captureDates).when(persistence).save(Mockito.any(Entity.class));

    service.foo();

    Assert.assertNull(captureDates.getCapturedValues().get(0));
}

private Date getEntityDate(InvocationOnMock invocation) {
    Entity entity = (Entity)invocation.getArguments()[0];
    return entity.getDate();
}

The capture completed by the rendered answer implementation cannot be implemented using mockitos argumentcaptor because it is only used after the method under test is called