class TestGuiManager(unittest.TestCase):
    def test_attempt_login_with_correct_credentials(self):
        # Arrange
        the_one_tk = Tk()
        database = My_Database('timetabler.db')
        my_login = GuiManager(the_one_tk, database)
        my_login.username_input.insert(0, "student")
        my_login.password_input.insert(0, "student1")
        my_login.selected.get()
        database.set_login_gui(my_login)
        my_login.display_login_window()
        my_login.finalise()

        # Act
        my_login.display_login_window()
        my_login.attempt_login()