}
@Test public void createDeleteTest() {
Teacher t = new Teacher("Name");
ClassGroup cls = new ClassGroup("Name", "description");
Teaches te = TeachingManager.getInstance().add(t, cls);
Assert.assertTrue(TeachingManager.getInstance().contains(te));
Assert.assertTrue(TeachingManager.getInstance().delete(te));
Assert.assertFalse(TeachingManager.getInstance().contains(te));
}