How do I verify a non-generic event was raised?

[tencek]

I know there's public static RaisedEvent<T> Raises<T>(...) in EventAsserts.cs but that only works for the EventHandler<TEventArgs>, AFAIK.
My event is of plain EventHandler type and I'd like to verify it was raised.
I ended up implementing it a bit dummy way on my own, here's the code:

    public class Testing
    {
        public static void RaisesEvent(
            Action<EventHandler> attach,
            Action<EventHandler> detach,
            Action testCode)
        {
            bool isEventRaised = false;
            var eventHandler = new EventHandler(delegate
            {
                isEventRaised = true;
            });

            attach(eventHandler);
            testCode();
            detach(eventHandler);

            Assert.True(isEventRaised);
        }
    }

Is there a way to achieve that using a standard xunit tools?
If not, would you consider adding it?

[bradwilson]

Yep, this is trivial for me to add.

Note: these will be RaisesAny and RaisesAnyAsync variants, not Raises and RaisesAsync because I will not be testing for exact types; anything which returns a value of EventArgs or anything derived from EventArgs will suffice. The reason is that trying to support an exact type match would yield the exact same signature as the existing Assert.Raises<T> method, since you'd need a generic type T to describe what the exact EventArgs-compatible type is that you want to test for.

Therefore, if you want to test for an exact type, you will need to run two assertions: Assert.RaisesAny to ensure the event was raised, followed by an Assert.IsType<T> against the returned RaisedEvent.Arguments property.

[bradwilson]

Fixed in #2773.

[tencek]

Thank you, that went fast! (-:
I'll give it a try.

[ChesireFreeThrow]

What about with events like in INotifyPropertyChanged using event PropertyChangedEventHandler? PropertyChanged; without a generic deinition?

this works for me:

ISupportInitializeNotification sut = new TestService();

            var evt = Assert.RaisesAny(h => sut.Initialized += h, h => sut.Initialized -= h, () => sut.BeginInit());

            Assert.NotNull(evt);
            Assert.Equal(sut, evt.Sender);
            Assert.IsType<EventArgs>(evt.Arguments);

but not this:

var sut = new TestService();

            var evt = Assert.RaisesAny(h => sut.PropertyChanged += h, h => sut.PropertyChanged -= h, () => sut.BeginInit());

            Assert.NotNull(evt);
            Assert.Equal(sut, evt.Sender);
            Assert.IsType<PropertyChangedEventArgs>(evt.Arguments);

[bradwilson]

@ChesireFreeThrow Please open an issue with a full repro project. Thanks!