public void UserNameAlreadyTaken() { // Arrange var user1 = new User(UserId: 1, Username: "******", Password: "******", "", "", DateTime.Now, "", "", ""); var user2 = new User(UserId: 2, Username: "******", Password: "******", "", "", DateTime.Now, "", "", ""); // Act userBusinessLogic.Add(user1); userBusinessLogic.Add(user2); // Assert // ExpectedException }