@Test
public void scanForSagas_reflectionsCtor_returnsEmptyListFromReflectionsParam() {

    // given
    Reflections reflections = mock(Reflections.class);
    when(reflections.getSubTypesOf(any(Class.class))).thenReturn(new HashSet<>());
    ReflectionsTypeScanner sut = new ReflectionsTypeScanner(reflections);
    // when
    Collection<Class<? extends Saga>> foundSagas = sut.scanForSagas();
    // then
    assertThat("Expected return value to be an empty list.", foundSagas.size(), equalTo(0));
}