@Test
public void whenGetByIdWithExistingIdItShouldReturnEntity() throws EntityNotFoundException {

    when(gateway.findById(TEST_ID)).thenReturn(domainEntity);
    TestEntity actual = service.getById(TEST_ID);
    verify(gateway).findById(TEST_ID);
    verifyNoMoreInteractions(gateway);
    assertThat(actual).isSameAs(domainEntity);
}