Verifying event registration using Moq

The moq 4.13 introduced this feature. Now it is possible to verify if add\remove has been invoked. Therefore four new methods have been introduced:

1. SetupAdd
2. SetupRemove
3. VerifyAdd
4. VerifyRemove

Example

var mock = new Mock<IAdder<EventArgs>>();
mock.SetupAdd(m => m.Added += (sender, args) => { });

mock.Object.Added += (sender, args) => { };
mock.Object.Added += (sender, args) => { };

mock.VerifyAdd(m => m.Added += It.IsAny<EventHandler>(), Times.Exactly(2));

NB: Notice that in order to verify at least one setup should be added. The reason is to keep backward compatibility with the older version of moq.