TestingPlatformCaptureOutput=false does not work with .NET 9.0 SDK

[campersau]

Describe the bug

When running dotnet test -p:TestingPlatformCaptureOutput=false the output of the testing platform is not visible anymore with .NET 9.0 SDK.

Steps To Reproduce

1. Create a new xUnit v3 project (e.g. https://xunit.net/docs/getting-started/v3/cmdline#create-the-unit-test-project)
2. Uncomment <TestingPlatformDotnetTestSupport>true</TestingPlatformDotnetTestSupport> in the csproj
3. Run dotnet test -p:TestingPlatformCaptureOutput=false

Expected behavior

Output using .NET 8.0 SDK (8.0.404)

dotnet test -p:TestingPlatformCaptureOutput=false
  Run tests: 'MyFirstUnitTests\bin\Debug\net8.0\MyFirstUnitTests.dll' [net8.0|x64]
  xUnit.net v3 Microsoft.Testing.Platform Runner v1.0.0+5b41c61aa1 (64-bit .NET 8.0.11)

  Passed! - Failed: 0, Passed: 1, Skipped: 0, Total: 1, Duration: 433ms

  Testlaufzusammenfassung: Bestanden! - MyFirstUnitTests\bin\Debug\net8.0\MyFirstUnitTests.dll (net8.0|x64)
    total: 1
    failed: 0
    succeeded: 1
    skipped: 0
    duration: 569ms
  Tests succeeded: 'MyFirstUnitTests\bin\Debug\net8.0\MyFirstUnitTests.dll' [net8.0|x64]

Actual behavior

Output using .NET 9.0 SDK (9.0.101)

dotnet test -p:TestingPlatformCaptureOutput=false
  MyFirstUnitTests Test Erfolgreich (1,6s)

Testzusammenfassung: insgesamt: 1; fehlgeschlagen: 0; erfolgreich: 1; übersprungen: 0; Dauer: 1,4 Sek.
Erstellen von Erfolgreich in 3,7s

Additional context

See also: xunit/xunit#3092 (comment)

Documentation: https://learn.microsoft.com/dotnet/core/testing/unit-testing-platform-integration-dotnet-test#show-complete-platform-output

[Evangelink]

Hi @campersau,

Thanks for raising this issue. I can confirm that terminal logger of .NET 9 is breaking MTP experience... I'll raise the point with SDK team. In the meantime, you can use /tl:false to disable the terminal logger experience.