@Test
public void removeInvalidContexts_5_InvalidContextsFound() {

    // we restrict the access to the mockRepositoryEntry_okCourse
    when(okCourseMock.getAccess()).thenReturn(RepositoryEntry.ACC_OWNERS_AUTHORS);
    Set<Long> invalidContextsIds = notificationCourseAccessManager.removeInvalidContexts(subscriberIds);
    assertEquals(5, invalidContextsIds.size());
    assertTrue(invalidContextsIds.contains(contextId_privateCourse1));
    assertTrue(invalidContextsIds.contains(contextId_ok));
}