Raising Events

Let's say - for argument's sake - that we have an interface that has an event defined:

public interface IRobot
{ 
    event EventHandler FellInLove;
}

Now in a test where we have a faked instance of this interface we can raise that event whenever we want, specifying sender and event args. We could also omit the sender and the fake will be passed as sender to the event handler. There's also a convenience method for raising with empty event args.

var robot = A.Fake<IRobot>();

robot.FellInLove += (s, e) =>
    {
        Console.WriteLine("Yay!");
    };

// Raise the event!
robot.FellInLove += Raise.With(EventArgs.Empty);

// Use the overload for empty event args
robot.FellInLove += Raise.WithEmpty();

// Specify sender and event args explicitly:
robot.FellInLove += Raise.With(sender: robot, e: EventArgs.Empty);

Events of type EventHandler<TEventArgs> may be raised in exactly the same way.

If an event is defined using a custom delegate, such as delegate void CustomEventHandler(object sender, FileSystemEventArgs eventArgs), it needs to be raised using Now:

robot.FoundANewFile += Raise.With(robot, new FileSystemEventArgs(…)).Now;

Just as when we're trying to ov erride a method's behavior, for FakeItEasy to raise an event, the event must be virtual (if defined on a class) or defined on an interface.

VB.Net

AddHandler robot.FellInLove, AddressOf Raise.With(EventArgs.Empty)