Microsoft.TemplateEngine.Authoring.TemplateVerifier package blocks upgrading past XUnit 2.x

[baronfel]

Product

dotnet CLI (dotnet new)

Describe The Bug

The template verifier helper package enforces a requirement of Xunit v2, however this stack is outdated - xunit v3 is released, and the Microsoft Testing Platform support is a thing that teams want to on board to. Our pinning to older xunit blocks that transition.

The cause of this is the 'UsesVerify' attribute creation + injection that we do here in the Verification engine.

We need to break this dependency - we should be able to express this verification as a normal extension method that works on top of the agnostic Verify core without any test-framework-specific dependencies required.

To Reproduce

Try to add the template verifier package to a project that uses xunit v3.

dotnet Info

Unnecessary

Visual Studio Version

No response

Additional context

No response

[marcpopMSFT]

dotnet/arcade#15654
Moving to V3 requires setting TestRunnerName to XUnitv3 first.

[marcpopMSFT]

Looks like @Youssef1313 did the migration for aspire which is one of the only dotnet repos on V3. We should sync to understand what was the work required though looks like they created their own copy of the arcade targets to get unblocked.

[Youssef1313]

@marcpopMSFT Aspire doesn't use latest Arcade (they are sticking with Arcade 9 for now). That's why some targets had to be replicated, but we are aiming to simplify this once they update to Arcade 10.

For the update, I'd start by setting TestRunnerName to XUnitV3 and work on any build errors or issues from there.