Verify that all getter methods are called

Question

I have the following test where I need to verify that all getters of the Person class are being called. So far I have used mockito's verify() to make sure that each getter is called. Is there a way to do that by reflection? It can be the case that a new getter is added to the Person class but the test will miss that.

public class GetterTest {
    class Person{

        private String firstname;
        private String lastname;

        public String getFirstname() {
            return firstname;
        }

        public String getLastname() {
            return lastname;
        }
    }

    @Test
    public void testAllGettersCalled() throws IntrospectionException{
        Person personMock = mock(Person.class);
        personMock.getFirstname();
        personMock.getLastname();

        for(PropertyDescriptor property : Introspector.getBeanInfo(Person.class).getPropertyDescriptors()) {
            verify(personMock, atLeast(1)).getFirstname();
            //**How to verify against any getter method and not just getFirstName()???**
        }
    }
}

Answer 1

Generally, don't mock the class under test. If your test is for a Person, you shouldn't ever see Mockito.mock(Person.class) in it, as that's a pretty clear sign that you're testing the mocking framework instead of the system-under-test.

Instead, you may want to create a spy(new Person()), which will create a real Person implementation using a real constructor and then copy its data to a Mockito-generated proxy. You can use MockingDetails.getInvocations() to reflectively check that every getter was called.

// This code is untested, but should get the point across. Edits welcome.
// 2016-01-20: Integrated feedback from Georgios Stathis. Thanks Georgios!

@Test
public void callAllGetters() throws Exception {
  Person personSpy = spy(new Person());
  personSpy.getFirstname();
  personSpy.getLastname();

  assertAllGettersCalled(personSpy, Person.class);
}

private static void assertAllGettersCalled(Object spy, Class<?> clazz) {
  BeanInfo beanInfo = Introspector.getBeanInfo(clazz);
  Set<Method> setOfDescriptors = beanInfo.getPropertyDescriptors()
      .stream()
      .map(PropertyDescriptor::getReadMethod)
      .filter(p -> !p.getName().contains("getClass"))
      .collect(Collectors.toSet());
  MockingDetails details = Mockito.mockingDetails(spy);
  Set<Method> setOfTestedMethods = details.getInvocations()
      .stream()
      .map(InvocationOnMock::getMethod)
      .collect(Collectors.toSet());
  setOfDescriptors.removeAll(setOfTestedMethods);
  // The only remaining descriptors are untested.
  assertThat(setOfDescriptors).isEmpty();
}

There might be a way to call verify and invoke on the Mockito-generated spy, but that seems very fragile, and very dependent on Mockito internals.

As an aside, testing bean-style getters seems like an odd use of time/effort. In general focus on testing implementations that are likely to change or break.