Migrate dotnet-MsiInstallation.Tests to MSTest.Sdk on MTP

[Evangelink]

Part of the ongoing xUnit -> MSTest.Sdk (MTP) test migration of the .NET SDK test suite, following the same pattern as the other open migration PRs (builds on the foundation merged in #54845).

Preserves the Windows-only test-app behaviour (non-Windows builds as a plain library via IsTestApplication=false); the [Collection] VM serialization becomes [DoNotParallelize] (inherited by the derived test classes).

Standard transformations: Microsoft.NET.Sdk -> MSTest.Sdk, the TestFramework project reference -> Microsoft.NET.TestFramework.MSTest, [Fact]/[Theory] -> [TestMethod], [InlineData] -> [DataRow], xUnit asserts -> MSTest (including the repo Recommended-mode idiomatic asserts), and ITestOutputHelper constructor injection removed in favour of the base SdkTest Log / TestContext.

Builds clean for the SDK target framework.

[Copilot]

Pull request overview

Migrates the dotnet-MsiInstallation.Tests VM-based MSI installation test project from xUnit to MSTest.Sdk (Microsoft Testing Platform), aligning it with the repo’s ongoing xUnit → MSTest migration strategy.

Changes:

• Switched test project SDK and references to MSTest.Sdk + Microsoft.NET.TestFramework.MSTest, and added needed Using items for MSTest-based builds.
• Converted xUnit attributes to MSTest equivalents ([Fact]/[Theory] → [TestMethod], [InlineData] → [DataRow], Skip → [Ignore]) and removed ITestOutputHelper ctor injection.
• Replaced xUnit collection-based serialization with MSTest parallelization control via [DoNotParallelize] on the VM base class.

Show a summary per file

File	Description
test/dotnet-MsiInstallation.Tests/WorkloadSetTestsBase.cs	Updates base test class ctor to MSTest-style (no output helper injection).
test/dotnet-MsiInstallation.Tests/WorkloadSetTests2.cs	Converts test class/attributes to MSTest and adds [TestClass].
test/dotnet-MsiInstallation.Tests/WorkloadSetTests.cs	Converts test class/attributes to MSTest, including skip handling via [Ignore].
test/dotnet-MsiInstallation.Tests/VSWorkloadTests.cs	Converts test class/attributes to MSTest and removes output-helper ctor injection.
test/dotnet-MsiInstallation.Tests/MsiInstallerTests.cs	Converts test class/attributes to MSTest and removes output-helper ctor injection.
test/dotnet-MsiInstallation.Tests/Framework/VMTestBase.cs	Updates VM test base for MSTest, including removing xUnit collection usage.
test/dotnet-MsiInstallation.Tests/dotnet-MsiInstallation.Tests.csproj	Switches to MSTest.Sdk, updates test framework reference, and adds MSTest-specific global usings.

Copilot's findings

• Files reviewed: 7/7 changed files
• Comments generated: 2

[Evangelink]

/ba-g unrelated razor test:

Exception Message

Expected value to be 0 because Expected command to pass but it did not.
Working Directory: /private/tmp/helix/working/A8100924/t/dotnetSdkTests.xRYmF5XE/Publish_WithP---7D4040F0
File Name: /tmp/helix/working/A8100924/p/d/dotnet
Arguments: msbuild /t:Publish /private/tmp/helix/working/A8100924/t/dotnetSdkTests.xRYmF5XE/Publish_WithP---7D4040F0/AppWithP2PReference/AppWithP2PReference.csproj /p:_IsPublishing=true /restore /p:BuildProjectReferences=false /p:ErrorOnDuplicatePublishOutputFiles=false /bl
Exit Code: 139
StdOut:
MSBuild version 18.9.0-preview-26311-113+50e862b8d for .NET
  Determining projects to restore...
[createdump] Gathering state for process 87429
[createdump] Crashing thread ce87a signal 11 (000b)
[createdump] Writing crash report to file /tmp/helix/working/A8100924/w/C2720A2E/uploads/coredump.87429.crashreport.json
[createdump] Crash report successfully written
[createdump] Writing full dump to file /tmp/helix/working/A8100924/w/C2720A2E/uploads/coredump.87429
[createdump] Written 6898913704 bytes (421076 pages) to core file
[createdump] Target process is alive
[createdump] Dump successfully written in 41624ms
StdErr:
, but found 139 (difference of 139).

CallStack

at FluentAssertions.Execution.LateBoundTestFramework.Throw(String message)
   at FluentAssertions.Execution.DefaultAssertionStrategy.HandleFailure(String message)
   at FluentAssertions.Execution.AssertionChain.FailWith(Func`1 getFailureReason)
   at Microsoft.NET.TestFramework.Assertions.CommandResultAssertions.Pass() in /_/test/Microsoft.NET.TestFramework/Assertions/CommandResultAssertions.cs:line 27
   at Microsoft.NET.Sdk.Razor.Tests.PublishIntegrationTest.Publish_WithP2P_WorksWhenBuildProjectReferencesIsDisabled() in /_/test/Microsoft.NET.Sdk.Razor.Tests/PublishIntegrationTest.cs:line 184
   at System.RuntimeMethodHandle.InvokeMethod(ObjectHandleOnStack target, Void** arguments, ObjectHandleOnStack sig, BOOL isConstructor, ObjectHandleOnStack result)
   at System.RuntimeMethodHandle.InvokeMethod(ObjectHandleOnStack target, Void** arguments, ObjectHandleOnStack sig, BOOL isConstructor, ObjectHandleOnStack result)
   at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)