I was setting up a new dev environment, and for this environment I went ahead and installed NUnit3TestAdapter so Visual Studio could discover the tests. However, although the the test were found there was a new error.
‘Unable to fetch source Information for test method’
The only solution I’ve found to this, is to disable the Dotnet Extensions for Test Explorer extension and restart Visual Studio (Visual Studio => Tools => Extensions and Updates). I haven’t had this problem before, so it might be a regression bug- and I therefore assume it will be fixed soon so we don’t need this workaround.