How do I run MSpec in Visual Studio's test system using Gallio?

Question

I'm trying to run MSpec tests in Visual Studio's test system using Gallio, but it appears to be ignoring the MSpec plugin from the IDE. What I did:

1. Installed Gallio
2. Added the MSpec NuGet package to my test project
3. Added the Gallio NuGet package to my test project
4. Copied the three files required for the MSpec Gallio integration to an "MSpec" folder in Gallio's installation directory
5. Wrote an MSpec test
6. Ran "All Tests in Solution" in the IDE

This yielded the following error

"No tests were run because no tests are loaded or the selected tests are disabled"

To check Gallio itself, I added a reference to MbUnit and created a simple MbUnit test. I also ran Gallio's other tools to check if the plugin was being picked up at all. I even restarted VS for good measure.

Results

Running the tests using Gallio.Echo or Gallio.Icarus successfully executes both MbUnit and MSpec tests, so the plugin is being picked up. Running the tests from Visual Studio runs the MbUnit test but not the MSpec test, so Gallio integration appears to be working (just not the MSpec plugin). Any thoughts?

Before anyone mentions it: yes, I'd rather be using ReSharper but licenses are not an option for my situation at the moment.

Answer 1

Update: The is now a project to integrate MSpec into VS2012's test system. It's available on the Visual Studio Gallery and the source is on GitHub.

After starting to debug the problem with both project's sources, it appears there are two underlying issues causing the incompatibility between MSpec and Gallio's VS runner. However, both issues stem from the fact that the VS runner uses Cecil to load type information from assemblies (presumably to avoid loading the test assembly into the main VS AppDomain).

I'll update this answer as I uncover more (hopefully resulting in one or more patch to fix the issues).

Issue 1: Nested types are ignored

I had been using nested types for my tests (SubjectSpec+when_something), which are ignored by the Cecil-based reflection used by Gallio's VS runner to avoid loading the test assembly into the app domain.

This ended up being a relatively simple fix, which I've submitted as a patch to the Gallio developers. I'll update this answer if/when I get confirmation of which release it will be part of.

Issue 2: MSpec causes "An exception occurred while invoking a test driver"

If the container type is removed to avoid issue 1, MSpec throws this error. The reason for this is that MSpec is trying to create an instance of the test object, but Gallio is only supplying it a wrapper Type object that can't actually be created.