Visual Studio 2012 Fakes not generating a stub for an interface that has a method with Stream return type

Question

Using Visual Studio 2012 to generate stubs with "Add Fakes Assembly", everything works as expected, except it is failing to generate a stub for this interface:

public interface IFileWrapper
{
    IEnumerable<string> ReadLines(string path);
    bool Exists(string path);
    Stream OpenReadStream(string path);
}

When I change the Stream to a FileStream (as Stream is an abstract class and I wanted to check if this is only happening with abstract classes), I am still not able to generate. When I remove the method signature completely (that is deleting Stream OpenReadStream(string path);), I am able to generate the stub.

This is my .fake file content:

<Fakes xmlns="http://schemas.microsoft.com/fakes/2011/" Diagnostic="true" Verbosity="Noisy">
  <Assembly Name="System.IO.Abstractions"/>
  <StubGeneration>
    <Clear />
    <Add AbstractClasses="true"/>
    <Add Interfaces="true"/>
  </StubGeneration>
  <ShimGeneration>
    <Clear />
  </ShimGeneration>
</Fakes>

1. Any idea why is this happening and how can I avoid it?
2. There is supposed to be a Visual Studio output panel where the Fake generation results will display. I can't see any and they are not displaying in the regular build panel. Any ideas where I can find it? I searched all VS 2012 menus.

Answer 1

This is caused by a limitation in the Fakes' current implementation. You can work around this problem by switching the target framework in your unit test project from 4.0 to 4.5.