There aren't any VS Code specific tests for cohosting at the moment, instead our coverage comes from the existing tests against MS.VS.LanguageServices.Razor. This is passable because most of the code is in a shared project, but it does mean that the tests are only running on Windows.

We share a lot of the code, we should be able to share a lot of the test code, but get coverage of the VS Code bits, and also coverage on Mac and Linus to boot.