[tests] Skip XslCompiledTransformApi tests on iOS, tvOS, and when testing native AOT

[mdh1418]

Fixes #75699

In effort to consolidate System.Private.Xml Test projects, the test suite exclusions within https://github.com/dotnet/runtime/blob/main/src/libraries/tests.proj weren't being honored because the suites no longer existed.

Instead, to skip the tests, [ConditionalClass(typeof(PlatformDetection), nameof(PlatformDetection.IsReflectionEmitSupported))] is being added at the class level to skip tests where Reflection Emit is needed.

This PR skips tests within XslCompiledTransformAp and XmlSerializerTests

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this PR. If you have write-permissions please help me learn by adding exactly one area label.

[mdh1418]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[MichalStrehovsky]

It might be better to put [ConditionalClass(typeof(PlatformDetection), nameof(PlatformDetection.IsReflectionEmitSupported))] on the individual test classes in these files. It's more consistent with how we do things and more futureproof.

[mdh1418]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[stephentoub]

LGTM if it fixes the problem.

[filipnavara]

It fixes half of the problem. Other half of the NativeAOT tests still fail and need similar treatment.

[mdh1418]

This PR was initially only targeting XslCompiledTransformApi tests, so I didn't have a look at all the other test suites that were removed and where the respective TestExclusions weren't honored, but I'll look at the failing XmlSerializerTests tests. Would it make sense to make PRs on a test suite by test suite basis, or trying to tackle them all in this one PR?

[filipnavara]

I don't know what triggered it but my totally unrelated PR started seeing the same errors on the NativeAOT pipelines. In fact I started getting them locally for the main branch when building the NativeAOT tests. That's why I started watching this PR since it resolves a sizeable amount of the failures. I appreciate that you started looking into it even if it was not for the same underlying reason.

Btw, you should run the extras pipelines (/azp run runtime-extra-platforms) once you are reasonably sure that the tests from the previous run are now marked correctly.

[MichalStrehovsky]

don't know what triggered it but my totally unrelated PR started seeing the same errors on the NativeAOT pipelines

The test projects (mentioned in the diffs to src/libraries/tests.proj in this PR) got deleted and folded into another project that is not excluded. So tests we weren't even compiling before started failing.

[filipnavara]

The test projects (mentioned in the diffs to src/libraries/tests.proj in this PR) got deleted and folded into another project that is not excluded. So tests we weren't even compiling before started failing.

Ah, that explains it. I can understand that it was missed as part of a PR if the extras pipelines were not run but I am quite surprised that there was no issue filed for it based on the rolling builds.

[stephentoub]

#75699 (comment)

[filipnavara]

#75699 (comment)

Missed that one (or rather it was not filed yet when I first hit the issue). Thanks.

[mdh1418]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mdh1418]

It fixes half of the problem. Other half of the NativeAOT tests still fail and need similar treatment.

I looked at the test failures more closely, and it doesn't look obviously System.Reflection.Emit to me.
Seeing errors like System.InvalidOperationException : There is an error in XML document (2, 14).

I looked at the comment in tests.proj and it looks like System.XmlSerializer is just not supported on NativeAOT right now.

I also noticed some test failures in two more suites that were removed System.Xml.Xsl.XslCompiledTransformApi.Tests.csproj however there doesn't seem to be a test suite skip in tests.proj, so not sure how these were skipped in the past. They were failing with

System.Xml.XmlSchemaValidatorApiTests.VerifyException : Error while loading assembly
   at System.Xml.XmlSchemaValidatorApiTests.ExceptionVerifier..ctor(String assemblyName, ExceptionVerificationFlags flags, ITestOutputHelper output) + 0x5fd
   at System.Xml.XmlSchemaValidatorApiTests.TCInitialize..ctor(ITestOutputHelper output) + 0x48
   at System.Private.Xml.Tests!<BaseAddress>+0x12ad20d
   at System.Reflection.DynamicInvokeInfo.Invoke(Object thisPtr, IntPtr methodToCall, Object[] parameters, BinderBundle binderBundle, Boolean wrapInTargetInvocationException) + 0x150

[filipnavara]

I looked at the test failures more closely, and it doesn't look obviously System.Reflection.Emit to me.
Seeing errors like System.InvalidOperationException : There is an error in XML document (2, 14).

It's a bit misleading but if you look closely at the stack trace the inner exception is still PlatformNotSupportedException due to unsupported Reflection Emit.

[mdh1418]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jkotas]

This is not fixing the whole problem, but it is still an improvement. Merging.

[jkotas]

Actually, I do not think that the condition on the Schema and XmlSerializer test is right (it should not be ReflectionEmit). The Xslt one is good, so let's merge that one at least.