Resharper Unit Tests not running

Make sure you aren't doing what I was doing and completely forget that solution is in release mode with test project set to build only in debug mode ;-)

I think restarting the whole system may have been a little premature. I have found when this happens all you need to do is restart Resharper.

I usually do this from the Command Window in Visual Studio , you just need to type these commands one after the other

Resharper_Suspend
Resharper_Resume

this generally fixes the problem for me and doesn't require reopening the solution.

If this fails you can clear the resharper caches. Information can be viewed here on how to do that.

here is how to do it from VS menu

There was a bug in ReSharper 2017.3.1, which was fixed in 2017.3.2: https://blog.jetbrains.com/dotnet/2018/02/01/resharper-ultimate-2017-3-2-bugfix/

You can update using ReSharper > Help > Check for Updates.

You can see if you had the same error by enabling logs. This is what I had:

--- EXCEPTION #2/2 [LoggerException]
Message = “Passed version string '2.1.101' doesn't look to be a valid .net core sdk version”

And eventually:

|W| UnitTestLaunch | System.NullReferenceException: Object reference not set to an instance of an object.
at JetBrains.ReSharper.UnitTestProvider.nUnit.v30.NUnitServiceProvider.GetRunStrategy(IUnitTestElement element)
at JetBrains.ReSharper.UnitTestProvider.nUnit.v30.Elements.NUnitElementBase.GetRunStrategy(IHostProvider hostProvider)
at JetBrains.ReSharper.UnitTestFramework.Launch.Stages.BuildStage.CollectProjectsToBuild()
at JetBrains.ReSharper.UnitTestFramework.Launch.Stages.BuildStage.Run(CancellationToken token)
at JetBrains.ReSharper.UnitTestFramework.Launch.UnitTestLaunch.RunStage(Object stageObject)

My project is using NET471, and I run ReSharper 2017.3.1 in Visual Studio 15.6.27428.2005