[Source Breaking (only for framework authors)]: Support test artifacts in VS

[Youssef Fahmy (Youssef1313)]

Fixes #4934

This change is a breaking change for framework authors. Framework authors will now need to add attachments to TestNode properties as TestFileArtifactProperty. There can be multiple of such property, or none at all.

Publishing TestNodeFileArtifact is no longer the way to report artifacts. The type is marked obsolete but is kept for binary compatibility.

Data consumers who used to consume TestNodeFileArtifact will instead need to consume TestNodeUpdateMessage and find the artifacts in the properties of the test node.

Tested in Playground:

code:

[TestClass]
public class TestClass
{
    public TestContext TestContext { get; set; }

    [TestMethod]
    [DataRow(0, UnfoldingStrategy = TestDataSourceUnfoldingStrategy.Fold)]
    [DataRow(1, UnfoldingStrategy = TestDataSourceUnfoldingStrategy.Fold)]
    public void TestMethod1(int x)
    {
        for (int i = 0; i < 5; i++)
        {
            TestContext.AddResultFile($"File #{i} for test case {x}");
        }
    }
}

Artur Spychaj (@drognanar) The order of attachments is reversed compared to VSTest, I think. But that seems to be on Test Explorer side.

FYI Brad Wilson (@bradwilson) Tom Longhurst (@thomhurst)

Also Terje Sandstrom (@OsirisTerje). As you are relying on VSTestBridge, you will only need to bump MTP version so that attachments start to show correctly in Test Explorer.

[Marco Rossignoli (MarcoRossignoli)]

Nit on name LGTM

[Jakub Jareš (nohwnd)]

Do you know who we are breaking with this? Is this all nunit, xunit, mstest and tunit?

[Youssef Fahmy (Youssef1313)]

Do you know who we are breaking with this? Is this all nunit, xunit, mstest and tunit?

xUnit and TUnit. For MSTest, we are always using the current version of VSTestBridge which accounts for the break in this PR. For NUnit, they are also good as they will just update VSTestBridge and that's it.

[Jakub Jareš (nohwnd)]

Does sound reasonable to me to make this change when we know the break is only for test framework authors. :) (how about Expecto?)

[Amaury Levé (Evangelink)]

Expecto also relies on the bridge so it's also only a matter of bumping version.

[Tom Longhurst (thomhurst)]

Happy to make this change.

Session Artifacts will remain as they are today?

[Youssef Fahmy (Youssef1313)]

Tom Longhurst (@thomhurst) Yes, session artifacts are still the same. This only affects TestNodeFileArtifact which previously didn't show up in VS at all.

[Brad Wilson (bradwilson)]

Is this change pushed to NuGet yet? If not, is there a planned release vehicle & timing?

[Youssef Fahmy (Youssef1313)]

Brad Wilson (@bradwilson) It will be available in 1.7. We may want to release a preview of 1.7 sometime soon.

[Brad Wilson (bradwilson)]

Available in xUnit.net v3 3.0.0-pre.4 https://xunit.net/docs/using-ci-builds