The Workaround:
Have you tried in Visual Studio going to ReSharper -> Options -> Tools -> Unit Testing
Change the setting “Run up to 1 assemblies in parallel” to a higher number. I tried one for each test project. Max is number of cores, I think.
Counterintuitive I know, but it worked for me and I am using AppDomain.CurrentDomain.BaseDirectory in the failing tests
The Cause
A caching optimization bug in ReSharper 8. Working Directory is not set properly. Perhaps running in parallel creates a separate process for each test, so they don’t trip over each other’s settings.
The Fix
JetBrains claim that this will be fixed in version 8.0.1
Update: There is a new unit testing option added in Resharper 8.1 to accomodate this scenario. Find it at ReSharper -> Options -> Tools -> Unit Testing -> “Use Separate AppDomain for each assembly with tests.
We see the same issue. I think it’s a bug. See: http://youtrack.jetbrains.com/issue/RSRP-380761