Don't inject Test target when TestingPlatformDisableCustomTestTarget is true

Author: Youssef1313

src/Platform/Microsoft.Testing.Platform.MSBuild/buildMultiTargeting/Microsoft.Testing.Platform.MSBuild.CustomTestTarget.targets

@@ -0,0 +1,6 @@
+<Project>
+  <!-- Expose a test target usable by tests projects where this target is injected -->
+  <Target Name="Test" Condition=" '$(UseMSBuildTestInfrastructure)' != 'True' " >
+    <CallTarget Targets="_TestingPlatformTest" />
+  </Target>
+</Project>

src/Platform/Microsoft.Testing.Platform.MSBuild/buildMultiTargeting/Microsoft.Testing.Platform.MSBuild.targets

@@ -267,10 +267,10 @@
     <CallTarget Targets="_TestingPlatformTest" />
   </Target>
 
-  <!-- Expose a test target usable by tests projects where this target is injected -->
-  <Target Name="Test" Condition=" '$(UseMSBuildTestInfrastructure)' != 'True' AND '$(TestingPlatformDisableCustomTestTarget)' == 'False' " >
-    <CallTarget Targets="_TestingPlatformTest" />
-  </Target>
+  <!-- The Test target is separated so that we can conditionally define it. -->
+  <!-- Putting a condition on a target determines whether the target is **executed** or not -->
+  <!-- We want to not define the Test target in the first place when the user sets TestingPlatformDisableCustomTestTarget to true -->
+  <Import Project="Microsoft.Testing.Platform.MSBuild.CustomTestTarget.targets" Condition="'$(TestingPlatformDisableCustomTestTarget)' == 'False'" />
 
   <Target Name="_TestingPlatformTest">
     <!-- We call VSTest built-in workflow only for the multi-tfm for single tfm we need to directly call our target -->

test/IntegrationTests/Microsoft.Testing.Platform.Acceptance.IntegrationTests/MSBuildTests.Test.cs

@@ -252,6 +252,21 @@ public async Task InvokeTestingPlatform_Target_Showing_Error_And_Do_Not_Capture_
         compilationResult.AssertOutputContains(".NET Testing Platform");
     }
 
+    [TestMethod]
+    public async Task TestingPlatformDisableCustomTestTarget_Should_Cause_UserDefined_Target_To_Run()
+    {
+        using TestAsset testAsset = await TestAsset.GenerateAssetAsync(
+            AssetName,
+            SourceCode
+            .PatchCodeWithReplace("$PlatformTarget$", "<PlatformTarget>x64</PlatformTarget>")
+            .PatchCodeWithReplace("$TargetFrameworks$", $"<TargetFramework>{TargetFrameworks.NetCurrent}</TargetFramework>")
+            .PatchCodeWithReplace("$AssertValue$", "true")
+            .PatchCodeWithReplace("$MicrosoftTestingPlatformVersion$", MicrosoftTestingPlatformVersion));
+        DotnetMuxerResult compilationResult = await DotnetCli.RunAsync($"build {testAsset.TargetAssetPath} -p:TestingPlatformDisableCustomTestTarget=true -p:ImportUserDefinedTestTarget=true -t:\"Build;Test\"", AcceptanceFixture.NuGetGlobalPackagesFolder.Path, failIfReturnValueIsNotZero: false);
+
+        compilationResult.AssertOutputContains("Error from UserDefinedTestTarget.targets");
+    }
+
     private const string SourceCode = """
 #file MSBuild Tests.csproj
 <Project Sdk="Microsoft.NET.Sdk">
@@ -270,6 +285,15 @@ public async Task InvokeTestingPlatform_Target_Showing_Error_And_Do_Not_Capture_
         <PackageReference Include="Microsoft.Testing.Platform.MSBuild" Version="$MicrosoftTestingPlatformVersion$" />
         <PackageReference Include="Microsoft.Testing.Platform" Version="$MicrosoftTestingPlatformVersion$" />
     </ItemGroup>
+
+    <Import Project="UserDefinedTestTarget.targets" Condition="'$(ImportUserDefinedTestTarget)' == 'true'" />
+</Project>
+
+#file UserDefinedTestTarget.targets
+<Project>
+    <Target Name="Test">
+        <Error Text="Error from UserDefinedTestTarget.targets" />
+    </Target>
 </Project>
 
 #file Program.cs