Add ImplicitMSTestUsings property to control MSTest implicit usings

The addition of this namespace to Implicit Usings is causing us problems because we make use of the System.ComponentModel.DescriptionAttribute in more places.

* Add ImplicitMSTestUsings property to control MSTest implicit usings
* Add comprehensive tests for ImplicitMSTestUsings property

Author: Copilot

src/Package/MSTest.Sdk/Sdk/VSTest/VSTest.targets

@@ -31,7 +31,7 @@
     Ensure feature is available and user hasn't opted-out from it.
     See https://github.com/dotnet/sdk/blob/f9fdf2c7d94bc86dc443e5a9ffecbd1962b1d85d/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.CSharp.props#L26-L34
     -->
-  <ItemGroup Condition=" '$(ImplicitUsings)' == 'true' Or '$(ImplicitUsings)' == 'enable' ">
+  <ItemGroup Condition="('$(ImplicitUsings)' == 'true' Or '$(ImplicitUsings)' == 'enable') And ('$(ImplicitMSTestUsings)' == '' Or '$(ImplicitMSTestUsings)' == 'true' Or '$(ImplicitMSTestUsings)' == 'enable')">
     <Using Include="Microsoft.VisualStudio.TestTools.UnitTesting" />
   </ItemGroup>
 

src/TestFramework/TestFramework.Extensions/buildTransitive/net6.0AndLater/MSTest.TestFramework.targets

@@ -25,7 +25,7 @@
     Ensure feature is available and user hasn't opted-out from it.
     See https://github.com/dotnet/sdk/blob/f9fdf2c7d94bc86dc443e5a9ffecbd1962b1d85d/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.CSharp.props#L26-L34
     -->
-  <ItemGroup Condition="'$(ImplicitUsings)' == 'true' Or '$(ImplicitUsings)' == 'enable'">
+  <ItemGroup Condition="('$(ImplicitUsings)' == 'true' Or '$(ImplicitUsings)' == 'enable') And ('$(ImplicitMSTestUsings)' == '' Or '$(ImplicitMSTestUsings)' == 'true' Or '$(ImplicitMSTestUsings)' == 'enable')">
     <Using Include="Microsoft.VisualStudio.TestTools.UnitTesting" />
   </ItemGroup>
 </Project>

src/TestFramework/TestFramework.Extensions/buildTransitive/others/MSTest.TestFramework.targets

@@ -5,7 +5,7 @@
     Ensure feature is available and user hasn't opted-out from it.
     See https://github.com/dotnet/sdk/blob/f9fdf2c7d94bc86dc443e5a9ffecbd1962b1d85d/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.CSharp.props#L26-L34
     -->
-  <ItemGroup Condition="'$(ImplicitUsings)' == 'true' Or '$(ImplicitUsings)' == 'enable'">
+  <ItemGroup Condition="('$(ImplicitUsings)' == 'true' Or '$(ImplicitUsings)' == 'enable') And ('$(ImplicitMSTestUsings)' == '' Or '$(ImplicitMSTestUsings)' == 'true' Or '$(ImplicitMSTestUsings)' == 'enable')">
     <Using Include="Microsoft.VisualStudio.TestTools.UnitTesting" />
   </ItemGroup>
 </Project>

test/IntegrationTests/MSTest.Acceptance.IntegrationTests/SdkTests.cs

@@ -446,6 +446,95 @@ public async Task SettingIsTestApplicationToFalseReducesAddedExtensionsAndMakesP
         Assert.IsFalse(binLog.FindChildrenRecursive<SL.Property>(p => p.Name == "OutputType").Any(p => p.Value == "Exe"));
     }
 
+    [TestMethod]
+    public async Task ImplicitMSTestUsings_WhenDisabled_DoesNotIncludeImplicitUsing()
+    {
+        using TestAsset testAsset = await TestAsset.GenerateAssetAsync(
+               AssetName,
+               SingleTestSourceCode
+               .PatchCodeWithReplace("$MSTestVersion$", MSTestVersion)
+               .PatchCodeWithReplace("$TargetFramework$", TargetFrameworks.NetCurrent)
+               .PatchCodeWithReplace("$ExtraProperties$", "<ImplicitMSTestUsings>false</ImplicitMSTestUsings>")
+               .PatchCodeWithReplace("using Microsoft.VisualStudio.TestTools.UnitTesting;", "// Explicit using removed to test implicit usings"));
+
+        // When ImplicitMSTestUsings is disabled, the compilation should fail because Microsoft.VisualStudio.TestTools.UnitTesting is not available
+        DotnetMuxerResult compilationResult = await DotnetCli.RunAsync($"build -c Debug {testAsset.TargetAssetPath}", AcceptanceFixture.NuGetGlobalPackagesFolder.Path, failIfReturnValueIsNotZero: false);
+
+        // Should fail to compile because TestClass and TestMethod are not available without the implicit using
+        compilationResult.AssertExitCodeIsNot(0);
+        compilationResult.AssertOutputContains("TestClass");
+    }
+
+    [TestMethod]
+    public async Task ImplicitMSTestUsings_WhenEnabled_IncludesImplicitUsing()
+    {
+        using TestAsset testAsset = await TestAsset.GenerateAssetAsync(
+               AssetName,
+               SingleTestSourceCode
+               .PatchCodeWithReplace("$MSTestVersion$", MSTestVersion)
+               .PatchCodeWithReplace("$TargetFramework$", TargetFrameworks.NetCurrent)
+               .PatchCodeWithReplace("$ExtraProperties$", "<ImplicitMSTestUsings>true</ImplicitMSTestUsings>")
+               .PatchCodeWithReplace("using Microsoft.VisualStudio.TestTools.UnitTesting;", "// Explicit using removed to test implicit usings"));
+
+        // When ImplicitMSTestUsings is enabled, the compilation should succeed because Microsoft.VisualStudio.TestTools.UnitTesting should be implicitly available
+        DotnetMuxerResult compilationResult = await DotnetCli.RunAsync($"build -c Debug {testAsset.TargetAssetPath}", AcceptanceFixture.NuGetGlobalPackagesFolder.Path);
+
+        compilationResult.AssertExitCodeIs(0);
+    }
+
+    [TestMethod]
+    public async Task ImplicitMSTestUsings_WhenEmpty_DefaultsToEnabled()
+    {
+        using TestAsset testAsset = await TestAsset.GenerateAssetAsync(
+               AssetName,
+               SingleTestSourceCode
+               .PatchCodeWithReplace("$MSTestVersion$", MSTestVersion)
+               .PatchCodeWithReplace("$TargetFramework$", TargetFrameworks.NetCurrent)
+               .PatchCodeWithReplace("$ExtraProperties$", string.Empty) // No ImplicitMSTestUsings property set
+               .PatchCodeWithReplace("using Microsoft.VisualStudio.TestTools.UnitTesting;", "// Explicit using removed to test implicit usings"));
+
+        // When ImplicitMSTestUsings is not set, it should default to enabled and compilation should succeed
+        DotnetMuxerResult compilationResult = await DotnetCli.RunAsync($"build -c Debug {testAsset.TargetAssetPath}", AcceptanceFixture.NuGetGlobalPackagesFolder.Path);
+
+        compilationResult.AssertExitCodeIs(0);
+    }
+
+    [TestMethod]
+    public async Task ImplicitMSTestUsings_WhenSetToDisable_DoesNotIncludeImplicitUsing()
+    {
+        using TestAsset testAsset = await TestAsset.GenerateAssetAsync(
+               AssetName,
+               SingleTestSourceCode
+               .PatchCodeWithReplace("$MSTestVersion$", MSTestVersion)
+               .PatchCodeWithReplace("$TargetFramework$", TargetFrameworks.NetCurrent)
+               .PatchCodeWithReplace("$ExtraProperties$", "<ImplicitMSTestUsings>disable</ImplicitMSTestUsings>")
+               .PatchCodeWithReplace("using Microsoft.VisualStudio.TestTools.UnitTesting;", "// Explicit using removed to test implicit usings"));
+
+        // When ImplicitMSTestUsings is disabled, the compilation should fail because Microsoft.VisualStudio.TestTools.UnitTesting is not available
+        DotnetMuxerResult compilationResult = await DotnetCli.RunAsync($"build -c Debug {testAsset.TargetAssetPath}", AcceptanceFixture.NuGetGlobalPackagesFolder.Path, failIfReturnValueIsNotZero: false);
+
+        // Should fail to compile because TestClass and TestMethod are not available without the implicit using
+        compilationResult.AssertExitCodeIsNot(0);
+        compilationResult.AssertOutputContains("TestClass");
+    }
+
+    [TestMethod]
+    public async Task ImplicitMSTestUsings_WhenSetToEnable_IncludesImplicitUsing()
+    {
+        using TestAsset testAsset = await TestAsset.GenerateAssetAsync(
+               AssetName,
+               SingleTestSourceCode
+               .PatchCodeWithReplace("$MSTestVersion$", MSTestVersion)
+               .PatchCodeWithReplace("$TargetFramework$", TargetFrameworks.NetCurrent)
+               .PatchCodeWithReplace("$ExtraProperties$", "<ImplicitMSTestUsings>enable</ImplicitMSTestUsings>")
+               .PatchCodeWithReplace("using Microsoft.VisualStudio.TestTools.UnitTesting;", "// Explicit using removed to test implicit usings"));
+
+        // When ImplicitMSTestUsings is set to 'enable', the compilation should succeed because Microsoft.VisualStudio.TestTools.UnitTesting should be implicitly available
+        DotnetMuxerResult compilationResult = await DotnetCli.RunAsync($"build -c Debug {testAsset.TargetAssetPath}", AcceptanceFixture.NuGetGlobalPackagesFolder.Path);
+        
+        compilationResult.AssertExitCodeIs(0);
+    }
+
     public sealed class TestAssetFixture() : TestAssetFixtureBase(AcceptanceFixture.NuGetGlobalPackagesFolder)
     {
         public const string AspireProjectName = "AspireProject";