public void RemoveEntrant() { Univercity U = new Univercity("test"); IStudent entrant1 = new Student(new FullName("test", "test", "test"), new DateTime(2000, 12, 14)); IStudent entrant2 = new Student(new FullName("test", "test", "test"), new DateTime(2000, 12, 14)); string id1 = entrant2.Id.ToString(); int result = 1; U.AddStudent(entrant1); U.AddStudent(entrant2); U.RemoveStudent(id1); CollectionAssert.Contains(U.Students, entrant1); CollectionAssert.DoesNotContain(U.Students, entrant2); Assert.AreEqual(U.Students.Count, result); }