NullReferenceException thrown when attempting to build unmet expectation message that includes an anonymous parameter

Hello. I’m using FakeItEasy to test F# projects, and I much prefer it over Moq 😃

However there is one problem, and that is when making assertion that a call must have happened, the assertion message it prints is misleading at best: System.ArgumentNullException: Value cannot be null. (Parameter 'value'). I wonder if this can be fixed somehow, either in my own code, or something you could fix on your side. I’ve included a small repository to to reproduce this issue, and also shows that it works as expected when testing a C# class

https://github.com/kaeedo/FakeItFSharp

I also noticed an old issue about adding an F# extension #232 . Any updates on that?

Thanks.

[blairconrad]

🥇 Thanks for the contribution @kaeedo. Look for your name in the release notes!

[thomaslevesque]

Actually, I see what the problem is: the Database implementation specifies a parameter name, but the interface doesn’t! If you just fix the interface to specify the parameter name, it should work as expected:

type IDatabase =
    abstract member Save: user: (int * string) -> unit

(we still need to fix the case where we don’t have the parameter name, though)