Faked method taking IDictionary<,> as argument should accept Dictionary<,>

I’m mocking a interface that uses interfaces in it’s argument list

  interface IBus {
    Task Send(object commandMessage, IDictionary<string, string> optionalHeaders = null);  
  }
}

At runtime this method is called with an actual dictionary. This results in the following exception being thrown:

System.AggregateException: One or more errors occurred. 
   (The faked method has the signature (System.Object, System.Collections.Generic.IDictionary`2[System.String,System.String]), 
   but invokes was used with (System.Object, System.Collections.Generic.Dictionary`2[System.String,System.String]).)
   ---> FakeItEasy.Configuration.FakeConfigurationException: 
    The faked method has the signature (System.Object, System.Collections.Generic.IDictionary`2[System.String,System.String]), 
    but invokes was used with (System.Object, System.Collections.Generic.Dictionary`2[System.String,System.String]).
   at FakeItEasy.ValueProducerSignatureHelper.AssertThatValueProducerSignatureSatisfiesCallSignature(MethodInfo callMethod, MethodInfo valueProducerMethod, String nameOfFeature) in C:\projects\fakeiteasy\src\FakeItEasy\ValueProducerSignatureHelper.cs:line 22

How can I make a fake accept this kind of calls?

[vegar]

Sorry. I’m wasting your time here. Of cause you are right. There was a call-setup with an invoke hidden in the test setup, and of cause it was using Dictionary instead of IDictionary.

[thomaslevesque]

Always glad to help!