Skipped unit tests should not show as "passed"

[lbussell]

We have lots of instances of skipping tests in this manner:

dotnet-docker/tests/Microsoft.DotNet.Docker.Tests/RuntimeDepsImageTests.cs

Lines 33 to 38 in ccbb4f2

	if (imageData.ImageVariant.HasFlag(DotNetImageVariant.AOT))
	{
	OutputHelper.WriteLine(
	$"Test is not applicable to AOT images. See {nameof(VerifyAotWebScenario)} instead.");
	return;
	}

However, returning early from a test will count as a "passed" test in Xunit, even if we didn't assert anything. This can lead to a false sense of confidence in test outcomes, especially for tests which are intended to be skipped temporarily.

We should find a way to make these tests show as "skipped" instead, like we do with Theories that have no data due to test filtering.

Xunit V3 (which is in preview) supports dynamic skipping of tests natively, but not Xunit V2. There's opportunity to use a library like Xunit.SkippableFact, which is used by several other Microsoft projects: Xunit.SkippableFact > used by ....

[lbussell]

Actually, Xunit v3 was released as 1.0.0 last month. I'll see how difficult the migration might be.