public static void Run()
{
Console.WriteLine($"{Environment.NewLine}*** OBSERVER PATTERN ***{Environment.NewLine}");
// Make a new bike manufacturer;
IBikeManufacturer manufacturer = new BikeManufacturer();
// Make some shops
IBikeShop roadBikeShop = new RoadBikeShop();
IBikeShop mountainBikeShop = new MountainBikeShop();
// Register the shops for updates
WeakReference <IBikeShop> roadBikeShopRef = manufacturer.RegisterShop(roadBikeShop);
WeakReference <IBikeShop> mountainBikehopRef = manufacturer.RegisterShop(mountainBikeShop);
// Announce some new bikes
manufacturer.NotifyShops(new BikeModel
{
Name = "Mountain King",
Type = BikeType.Mountain
});
manufacturer.NotifyShops(new BikeModel
{
Name = "Road Racer",
Type = BikeType.Road
});
}
public void BikeManufacturer_NotifyShops_HandlesNullReferences()
{
// Arrange
IBikeManufacturer manufacturer = new BikeManufacturer();
IBikeShop mShop = new MountainBikeShop();
WeakReference <IBikeShop> mShopRef = manufacturer.RegisterShop(mShop);
// null out the shop
mShop = null;
GC.Collect();
GC.WaitForPendingFinalizers();
// Act
manufacturer.NotifyShops(new BikeModel
{
Name = "test",
Type = Common.BikeType.Mountain
});
// Assert
// @Markmc27 this doesn't work if I mock it because I've first got to make the
// unregister call virtual and then the null mShop reference doesn't seemto be null any more.
// I think mock is caching it or copying it somewhere and preventing the GC from doing it's thing.
//mockManufacturer.Verify(m => m.UnregisterShop(It.IsAny<WeakReference<IBikeShop>>()), Times.Once);
}
public void BikeManufacturer_NotifyShops_NotifiesObservers()
{
// Arrange
IBikeManufacturer manufacturer = new BikeManufacturer();
Mock <IBikeShop> mockShop = new Mock <IBikeShop>();
WeakReference <IBikeShop> mShopRef = manufacturer.RegisterShop(mockShop.Object);
// Act
manufacturer.NotifyShops(new BikeModel
{
Name = "test",
Type = Common.BikeType.Mountain
});
// Assert
mockShop.Verify(m => m.NotifyAboutNewBike(It.IsAny <BikeModel>()), Times.Once);
}