Contains.Key no longer working for IDictionary

[ItsVeryWindy]

I had some tests that were checking for a key in the exception data property that have stopped working since updating the version of nunit.

Narrowing it down I believe it's because it only implements the non generic IDictionary and maybe a change has been made that hasn't taken that into account. This has stopped working since 3.11

It can be replicated fairly easily.
Assert.That(new Exception().Data, Contains.Key("hello"));

Previously this would return

Expected: dictionary containing key "hello"
But was:  <empty>

but now returns

System.ArgumentException : The ListDictionaryInternal value must have a ContainsKey or Contains(TKey) method.

[rprouse]

Thanks, it is odd that this was working before. We did make changes to include Exception data in messages, but knowing the nature of that change I don't think it is related.

[mikkelbu]

The regression was introduced in version 3.11, I guess in #2837 / #2994

The check only matches ContainsKey method or a Contains method in a generic class where the type parameter is called TKey and where the sole parameter of Contains have the type as TKey - see e.g. https://github.com/DaiMichael/nunit/blob/70b5915bd844cf1f08c558452e2427c66c3c68dc/src/NUnitFramework/framework/Constraints/DictionaryContainsKeyConstraint.cs#L227. There are some discussion about this choice in the issues and associated PRs.

So https://referencesource.microsoft.com/#mscorlib/system/collections/listdictionaryinternal.cs,184 does not match the current implementation.

[stevenaw]

Since this seems to be a regression, I figured we would want to fix it. I've made an attempt at fixing it in the linked PR.

[mikkelbu]

@stevenaw I think it makes sense to fix it, and had actually planned to look at it, but I've not had much time the last month or so. So great that you took a look at it.