xUnit tests are not discovered (and run) in a .Net9 UWP application

[vgromfeld]

Description

I've converted an UWP test application using xUnit as its test environment to .Net 9 + AOT.
The xUnit tests are not discovered (and not run).

Steps To Reproduce

1. Create an UWP test application
2. Import xUnit nuget package
3. Convert the project to a .Net 9 project
4. Add an MSTest class:

[TestClass]
public class msUnitTest
{
    [TestMethod]
    public void Test()
    {
        var a = 10;
        Assert.AreEqual(10, a);
    }
}

5. Add an xUnit test class

public class xUnitTest
{
    [Fact]
    public void Test()
    {
        var a = 10;
        a.Should().Be(10);
    }
}

7. Run the tests

Only the msTest.Test test is run.

Expected Behavior

All the tests should run.

Version Info

TargetFramework = net9.0-windows10.0.26100.0
Microsoft.NET.Test.Sdk = 17.14.0-preview-25107-01
MSTest = 3.8.2
xunit = 2.9.3
xunit.runner.visualstudio = 3.0.2

Additional Context

Sample test application: UnitTests.zip

[Sergio0694]

As a sanity check, can you verify whether they work with just MSTest 3.8.2 and that preview test SDK?
I'm interested in seeing if on your machine this is just an issue specific to xUnit. If so, it's likely an issue on their end.