public void the_time_of_clock_Moscow_should_be_5_after_the_phone_clock_is_set_to_9_Beijing_time()
        {
            //Arrange
            CityClock moscowClock = new CityClock(4);

            hotelWorldClockSystem.attach(moscowClock);

            //Act
            phoneClock.setHotelWorldClockSystem(hotelWorldClockSystem);
            phoneClock.setTime(9);

            //Assert
            Assert.AreEqual(5, moscowClock.getTime());
        }
        public void the_time_of_clock_NewYork_should_be_20_after_the_phone_clock_is_set_to_9_Beijing_time()
        {
            //Arrange
            CityClock newYorkClock = new CityClock(-5);

            hotelWorldClockSystem.attach(newYorkClock);

            //Act
            phoneClock.setHotelWorldClockSystem(hotelWorldClockSystem);
            phoneClock.setTime(9);

            //Assert
            Assert.AreEqual(20, newYorkClock.getTime());
        }
        public void the_time_of_clock_London_should_be_1_after_the_phone_clock_is_set_to_9_Beijing_time()
        {
            //Arrange
            CityClock londonClock = new CityClock(0);

            hotelWorldClockSystem.attach(londonClock);

            //Act
            phoneClock.setHotelWorldClockSystem(hotelWorldClockSystem);
            phoneClock.setTime(9);

            //Assert
            Assert.AreEqual(1, londonClock.getTime());
        }
        public void the_time_of_clock_London_and_NewYork_should_be_1_and_20_respectively_after_the_phone_clock_is_set_to_9_Beijing_time()
        {
            //Arrange
            CityClock londonClock  = new CityClock(0);
            CityClock newYorkClock = new CityClock(-5);

            hotelWorldClockSystem.attach(londonClock);
            hotelWorldClockSystem.attach(newYorkClock);

            //Act
            phoneClock.setHotelWorldClockSystem(hotelWorldClockSystem);
            phoneClock.setTime(9);

            //Assert
            Assert.AreEqual(1, londonClock.getTime());
            Assert.AreEqual(20, newYorkClock.getTime());
        }