public void TemperatureSensorShouldWork()
{
TemperatureSensor temperatureSensor = new TemperatureSensor();
Assert.AreEqual(false, temperatureSensor.IsOn(), "TemperatureSensor should start off!");
temperatureSensor.SetOn();
Assert.AreEqual(true, temperatureSensor.IsOn(), "TemperatureSensor should turn on with SetOn()!");
temperatureSensor.SetOff();
Assert.AreEqual(false, temperatureSensor.IsOn(), "TemperatureSensor should turn off with SetOff()!");
Assert.Throws <InvalidOperationException>(() => temperatureSensor.Read(), "TemperatureSensor should throw an InvalidOperationException if Read when off!");
}