BadImageFormatException from testhost.dll when using Visual Studio 2022 Preview

I am unable to run NUnit tests on the latest Visual Studio 2022 Preview. I get the following error, which I don’t know is due to a bug in the Preview, or a sign of changes to inevitably come.

Log level is set to Informational (Default).
Connected to test environment '< Local Windows Environment >'
Test data store opened in 0,159 sec.
========== Starting test discovery ==========
========== Test discovery skipped: All test containers are up to date ==========
Starting test discovery for requested test run
========== Starting test discovery ==========
Microsoft.VisualStudio.TestPlatform.ObjectModel.TestPlatformException: Testhost process exited with error: Unhandled exception. System.BadImageFormatException: Could not load file or assembly 'C:\Source\NUnitExplicitTest\Tests\bin\Debug\net6.0\testhost.dll'. An attempt was made to load a program with an incorrect format.
File name: 'C:\Source\NUnitExplicitTest\Tests\bin\Debug\net6.0\testhost.dll'
. Please check the diagnostic logs for more information.
   at Microsoft.VisualStudio.TestPlatform.CrossPlatEngine.Client.ProxyOperationManager.ThrowOnTestHostExited(Boolean testHostExited)
   at Microsoft.VisualStudio.TestPlatform.CrossPlatEngine.Client.ProxyOperationManager.SetupChannel(IEnumerable`1 sources, String runSettings)
   at Microsoft.VisualStudio.TestPlatform.CrossPlatEngine.Client.ProxyDiscoveryManager.DiscoverTests(DiscoveryCriteria discoveryCriteria, ITestDiscoveryEventsHandler2 eventHandler)
========== Test discovery aborted: 0 Tests found in 2,6 sec ==========
========== Starting test run ==========
Testhost process exited with error: Unhandled exception. System.BadImageFormatException: Could not load file or assembly 'C:\Source\NUnitExplicitTest\Tests\bin\Debug\net6.0\testhost.dll'. An attempt was made to load a program with an incorrect format.
File name: 'C:\Source\NUnitExplicitTest\Tests\bin\Debug\net6.0\testhost.dll'
. Please check the diagnostic logs for more information.
Testhost process exited with error: Unhandled exception. System.BadImageFormatException: Could not load file or assembly 'C:\Source\NUnitExplicitTest\Tests\bin\Debug\net6.0\testhost.dll'. An attempt was made to load a program with an incorrect format.
File name: 'C:\Source\NUnitExplicitTest\Tests\bin\Debug\net6.0\testhost.dll'
. Please check the diagnostic logs for more information.
========== Test run aborted: 0 Tests (0 Passed, 0 Failed, 0 Skipped) run in < 1 ms ==========

• NUnit and NUnit3TestAdapter versions
  • NUnit 3.13.2
  • NUnit3TestAdapter 4.2.0
• Visual Studio edition and full version number (see Help About)
  • Microsoft Visual Studio Enterprise 2022 (64-bit) - Preview Version 17.1.0 Preview 3.0
• A short repro, preferably attached or pointing to a git repo or gist
  • https://github.com/Stolpe/NUnitExplicitTest/tree/net60 (I lazily reused a repo from an earlier issue 😃)
• What .net platform and version is being targeted
  • .NET 6.0

[OsirisTerje]

Thanks! I’ve also notified @kendrahavens MS-PG directly.

[OsirisTerje]

@Stolpe Just tried it here with Preview 3, and it worked here too, and in the net60 branch.