.NET 6 tests require NUnit.Console 3.15.0 or later

[yfdyh000]

See the nunit/nunit-console#1101, nunit/nunit-console#1123 fixed this issue.

Appveyor still supply the NUnit.Console 3.13.0 by default.
error:
NUnit Console Runner 3.13.0 (.NET 2.0)
----> Could not load file or assembly 'System.Runtime, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.

A workaround based the post:

      before_build:
        - ps: |
           # nunit
           $nunitPath = "$env:SYSTEMDRIVE\Tools\NUnit3"
           Remove-Item $nunitPath -Recurse -Force
           $zipPath = "$env:TEMP\NUnit.Console-3.15.0.zip"
           $tempPath = "$env:TEMP\NUnit.Console"
           (New-Object Net.WebClient).DownloadFile('https://github.com/nunit/nunit-console/releases/download/3.15.0/NUnit.Console-3.15.0.zip', $zipPath)
           7z x $zipPath -y -o"$tempPath" | Out-Null
           [IO.Directory]::Move("$tempPath\bin\net6.0", $nunitPath)
           # logger
           $zipPath = "$env:TEMP\Appveyor.NUnit3Logger.zip"
           (New-Object Net.WebClient).DownloadFile('https://www.appveyor.com/downloads/Appveyor.NUnit3Logger.zip', $zipPath)
           7z x $zipPath -y -o"$nunitPath\addins" | Out-Null
           Move-Item "$nunitPath\addins\appveyor.addins" "$nunitPath\appveyor.addins"

Then,

      test_script:
        - C:\Tools\NUnit3\nunit3-console "C:\path\name.dll" -result=myresults.xml

however, appends the ;format=AppVeyor will be thrown Unknown result format: AppVeyor for now.

[FeodorFitsner]

Will try it during the next image update.

Wondering why are you not using dotnet test ... to test .NET Core projects?

[yfdyh000]

Wondering why are you not using dotnet test ... to test .NET Core projects?

Just try to fix the CI for the project, it originally worked. I'm not sure the difference between the two.