Support WithArgs assertion for .NET 4.5 EventHandlers about fluentassertions

[dennisdoomen]

Nobody has been asking for this in three years, so we're going to close it.

[dennisdoomen]

I like that.

[adamvoss]

There is a little bit of a complication to consider here.
.NET does not require an event to be an EventHandler: any delegate is allowed. That is, there is an existing issue of not having a FA method suitable for asserting against an event of type Action<int, string>. Removal of the type constraint would make WithArgs be able to be used in these cases; however, the implementation will give an erroneous failure when/if anyone ever asserts against an Event with repeated Type Parameters ex. Action<string, string>. It is easy enough to change the implementation so that it handles the case better, my main question is whether this is desired API for these types of assertions.

Example:

public event Action<string, string> Update;

subject
    .ShouldRaise("Update")
    .WithArgs<string>(args => args == "hi")
    .WithArgs<string>(args => args == "bye");

With this API, you would either need to add a restrictions to WithArgs that the method calls have to be ordered, or you would only be able to assert that the given args were used, but not which of the parameters they were used for.

[Tdue21]

This would make my life much simpler as well :)

[okobylianskyi]

I'm almost ready to provide PR for this issue, but I need to know the decision on @vossad01 question about repeated type parameters. My implementation currently sticks with second option. Should I rework it or it is enough just to assert that value was present among arguments of the same type?

[dennisdoomen]

You still want to wrap this up?