Element in unit tests left pending after completion

Since this is the first answer, when I searched the net and the above answers didn't solve it here is my solution:

Updating Resharper solved it for me.

Even though I had autoupdate enabled, a firewall prevented me from updating. Workaround was simply to download the offline-installer from https://www.jetbrains.com/resharper/download/#section=offline-installer and then manually update the version.

Version > 2020.2 should not have these issues.

It looks like a bug in ReSharper:

https://resharper-support.jetbrains.com/hc/en-us/community/posts/360000057490-Unit-Test-Sessions-reports-Inconclusive-Test-not-run-

https://youtrack.jetbrains.com/issue/RSRP-469301

Changing my Solution Platform to x64 from any CPU solved this issue for me.