I cloned this repo and ran the unit tests - both passed. I then updated all the NuGet packages to the latest versions, rebuilt and ran the tests - both failed. The latest NuGet package versions that were updated are as follows:
Akka.TestKit.Xunit2 (1.4.12)
Akkatecture.TestFixture (0.6.3)
Microsoft.NET.Test.Sdk (16.8.0)
Microsoft.NETCore.App (2.2.0)
xunit (2.4.1)
xunit.runner.visualstudio (2.4.3)