@Test
	public void unEnrollsStudentToActivity() {
		Student s = null;
		Activity a = null;
		try {
			s = familyService.findStudent(1);
			a = activityService.find(1);
		} catch (InstanceNotFoundException e) {
			fail("Activity not exists");
		}
		activityService.enrollmentStudentInActivity(s, a);

		activityService.unEnrollsStudentToActivity(s, a);

		assertFalse("Student is enrolled in the activity yet", s
				.getActivities().contains(a));
		assertFalse("Activity has the student enrolled yet", a.getStudents()
				.contains(s));

	}