MSTest project demonstrating AddResultFile not working with long filenames

.gitignore

/.vs
/bin
/obj
/TestResults

.runsettings

<?xml version="1.0" encoding="utf-8" ?>
<RunSettings>
  <MSTest>
    <DeleteDeploymentDirectoryAfterTestRunIsComplete>False</DeleteDeploymentDirectoryAfterTestRunIsComplete>
  </MSTest>
</RunSettings>

AddResultFileTest.csproj

<Project Sdk="MSTest.Sdk/3.9.3">

  <PropertyGroup>
    <TargetFramework>net9.0</TargetFramework>
    <LangVersion>latest</LangVersion>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <!--
      Displays error on console in addition to the log file. Note that this feature comes with a performance impact.
      For more information, visit https://learn.microsoft.com/dotnet/core/testing/unit-testing-platform-integration-dotnet-test#show-failure-per-test
      -->
    <TestingPlatformShowTestsFailure>true</TestingPlatformShowTestsFailure>
    <RunSettingsFilePath>$(MSBuildProjectDirectory)\.runsettings</RunSettingsFilePath>
  </PropertyGroup>

</Project>

AddResultFileTest.sln


Microsoft Visual Studio Solution File, Format Version 12.00
# Visual Studio Version 17
VisualStudioVersion = 17.14.36327.8 d17.14
MinimumVisualStudioVersion = 10.0.40219.1
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "AddResultFileTest", "AddResultFileTest.csproj", "{56F69267-3413-4BDA-95D1-8015C9C885FF}"
EndProject
Global
	GlobalSection(SolutionConfigurationPlatforms) = preSolution
		Debug|Any CPU = Debug|Any CPU
		Release|Any CPU = Release|Any CPU
	EndGlobalSection
	GlobalSection(ProjectConfigurationPlatforms) = postSolution
		{56F69267-3413-4BDA-95D1-8015C9C885FF}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
		{56F69267-3413-4BDA-95D1-8015C9C885FF}.Debug|Any CPU.Build.0 = Debug|Any CPU
		{56F69267-3413-4BDA-95D1-8015C9C885FF}.Release|Any CPU.ActiveCfg = Release|Any CPU
		{56F69267-3413-4BDA-95D1-8015C9C885FF}.Release|Any CPU.Build.0 = Release|Any CPU
	EndGlobalSection
	GlobalSection(SolutionProperties) = preSolution
		HideSolutionNode = FALSE
	EndGlobalSection
	GlobalSection(ExtensibilityGlobals) = postSolution
		SolutionGuid = {BE7DA027-F103-407C-AE27-C92C34A03668}
	EndGlobalSection
EndGlobal

MSTestSettings.cs

[assembly: Parallelize(Scope = ExecutionScope.ClassLevel)]

TestResultTests.cs

namespace AddResultFileTest;

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

	[TestMethod]
	public void AddResultFileInTestResultsDirectory()
	{
		string filePath = Path.Combine(TestContext.TestResultsDirectory!, "ResultFile.txt");
		File.WriteAllText(filePath, "Hello, World!");
		TestContext.AddResultFile(filePath);
	}

	[TestMethod]
	public void AddLongFilenameResultFileInTestResultsDirectory()
	{
		string fileDir = Path.Combine(TestContext.TestResultsDirectory!, new string('X', 250));
		Directory.CreateDirectory(fileDir);
		string filePath = Path.Combine(fileDir, "ResultFile.txt");
		File.WriteAllText(filePath, "Hello, World!");
		TestContext.AddResultFile(filePath);
	}

	[TestMethod]
	public void AddResultFileInTempDirectory()
	{
		string filePath = Path.GetTempFileName();
		File.WriteAllText(filePath, "Hello, World!");
		TestContext.AddResultFile(filePath);
	}
}