Drop MSTest's VSTest bridge dependency on the MTP path

src/Adapter/MSTest.TestAdapter/MSTest.TestAdapter.csproj

@@ -66,7 +66,8 @@
 
     <!-- Curated package dependencies. PrivateAssets="none" so all assets (including build/buildTransitive
          targets, e.g. from Microsoft.Testing.Platform.MSBuild) flow to consumers. -->
-    <ProjectReference Include="$(RepoRoot)src\Platform\Microsoft.Testing.Extensions.VSTestBridge\Microsoft.Testing.Extensions.VSTestBridge.csproj" Condition=" '$(TargetFramework)' != '$(UwpMinimum)' " PrivateAssets="none" />
+    <ProjectReference Include="$(RepoRoot)src\Platform\Microsoft.Testing.Extensions.TrxReport.Abstractions\Microsoft.Testing.Extensions.TrxReport.Abstractions.csproj" Condition=" '$(TargetFramework)' != '$(UwpMinimum)' " PrivateAssets="none" />
+    <ProjectReference Include="$(RepoRoot)src\Platform\Microsoft.Testing.Extensions.Telemetry\Microsoft.Testing.Extensions.Telemetry.csproj" Condition=" '$(TargetFramework)' != '$(UwpMinimum)' " PrivateAssets="none" />
     <ProjectReference Include="$(RepoRoot)src\Platform\Microsoft.Testing.Platform.MSBuild\Microsoft.Testing.Platform.MSBuild.csproj" Condition=" '$(TargetFramework)' != '$(UwpMinimum)' " PrivateAssets="none" />
     <!-- On Windows the package depends on MSTest.TestFramework, matching the historical MSTest.TestAdapter.nuspec.
          The historical MSTest.TestAdapter.NonWindows.nuspec did NOT declare this dependency, so on non-Windows builds
@@ -83,11 +84,11 @@
     <PackageReference Include="System.Threading.Tasks.Extensions" Condition=" '$(TargetFramework)' == '$(NetFrameworkMinimum)' OR '$(TargetFramework)' == '$(UwpMinimum)' " />
     <PackageReference Include="System.Memory" Condition=" '$(TargetFramework)' == '$(NetFrameworkMinimum)' OR '$(TargetFramework)' == '$(UwpMinimum)' " />
 
-    <!-- The adapter's VSTest-facing code (VSTestAdapter\*, AdapterTestProperties) uses the VSTest object model
-         directly. On other TFMs it flows in transitively via Microsoft.Testing.Extensions.VSTestBridge, but that
-         reference is not added for UWP (see above), and PlatformServices no longer references the object model,
-         so it is referenced explicitly here for UWP. -->
-    <PackageReference Include="Microsoft.TestPlatform.ObjectModel" Condition=" '$(TargetFramework)' == '$(UwpMinimum)' " />
+    <!-- The adapter's VSTest-facing code (VSTestAdapter\*, AdapterTestProperties) and the native Microsoft.Testing.Platform
+         integration (TestingPlatformAdapter\MSTestFilterContext) use the VSTest object model directly. It used to flow
+         in transitively via Microsoft.Testing.Extensions.VSTestBridge; now that the bridge reference is gone it is
+         referenced explicitly for every TFM. -->
+    <PackageReference Include="Microsoft.TestPlatform.ObjectModel" />
 
     <!-- The native Microsoft.Testing.Platform integration (TestingPlatformAdapter\MSTestFilterContext, guarded by
          !WINDOWS_UWP) parses VSTest filter expressions via the Filter source package. It flows in transitively via

src/Adapter/MSTest.TestAdapter/TestingPlatformAdapter/MSTestFilterContext.cs

@@ -19,9 +19,9 @@ namespace Microsoft.VisualStudio.TestPlatform.MSTest.TestAdapter.TestingPlatform
 /// context adapters.
 /// </summary>
 /// <remarks>
-/// This mirrors, for the MSTest native path, what <c>ContextAdapterBase</c> / <c>RunContextAdapter</c> /
-/// <c>DiscoveryContextAdapter</c> do in <c>Microsoft.Testing.Extensions.VSTestBridge</c>. The filter-expression
-/// parsing itself reuses the VSTest <c>Microsoft.TestPlatform.Filter.Source</c> package, exactly like the bridge.
+/// This mirrors, for the MSTest native path, the former bridge context-adapter behavior
+/// (<c>ContextAdapterBase</c> / <c>RunContextAdapter</c> / <c>DiscoveryContextAdapter</c>). The
+/// filter-expression parsing itself reuses the VSTest <c>Microsoft.TestPlatform.Filter.Source</c> package.
 /// </remarks>
 [SuppressMessage("ApiDesign", "RS0030:Do not use banned APIs", Justification = "We can use MTP from this folder")]
 internal abstract class MSTestFilterContextBase

src/Adapter/MSTest.TestAdapter/TestingPlatformAdapter/MSTestTestFramework.cs

@@ -23,19 +23,12 @@
 namespace Microsoft.VisualStudio.TestTools.UnitTesting;
 
 /// <summary>
-/// A native Microsoft.Testing.Platform (MTP) test framework for MSTest. Unlike <see cref="MSTestBridgedTestFramework"/>
-/// it does not derive from the VSTest bridge: it handles the MTP discovery/run requests directly, builds the run
-/// context, filter and runsettings natively (see <see cref="MSTestRunContext"/> / <see cref="MSTestDiscoveryContext"/>
-/// / <see cref="MSTestRunSettings"/>), and publishes test nodes through the native <see cref="MtpUnitTestElementSink"/>
-/// / <see cref="MtpTestResultRecorder"/>. It reuses MSTest's existing <see cref="MSTestDiscoverer"/> /
-/// <see cref="MSTestExecutor"/> engine.
+/// A native Microsoft.Testing.Platform (MTP) test framework for MSTest. It does not derive from the VSTest bridge:
+/// it handles the MTP discovery/run requests directly, builds the run context, filter and runsettings natively
+/// (see <see cref="MSTestRunContext"/> / <see cref="MSTestDiscoveryContext"/> / <see cref="MSTestRunSettings"/>), and
+/// publishes test nodes through the native <see cref="MtpUnitTestElementSink"/> / <see cref="MtpTestResultRecorder"/>.
+/// It reuses MSTest's existing <see cref="MSTestDiscoverer"/> / <see cref="MSTestExecutor"/> engine.
 /// </summary>
-/// <remarks>
-/// This is opt-in (behind <c>MSTEST_EXPERIMENTAL_NATIVE_MTP</c>) while the native path reaches full parity with the
-/// bridge. It still relies on the bridge only for the shared command-line options (<c>--filter</c>, <c>--settings</c>,
-/// <c>--test-parameter</c>) and the runsettings configuration/environment-variable providers; retiring those and the
-/// bridge package reference is the final step of the migration.
-/// </remarks>
 [SuppressMessage("ApiDesign", "RS0030:Do not use banned APIs", Justification = "We can use MTP from this folder")]
 [StackTraceHidden]
 internal sealed class MSTestTestFramework : ITestFramework, IDataProducer, IDisposable
@@ -44,7 +37,7 @@ internal sealed class MSTestTestFramework : ITestFramework, IDataProducer, IDisp
     private readonly Func<IEnumerable<Assembly>> _getTestAssemblies;
     private readonly IServiceProvider _serviceProvider;
     private readonly ITrxReportCapability? _trxReportCapability;
-    private readonly BridgedConfiguration _configuration;
+    private readonly PlatformServicesConfigurationAdapter _configuration;
     private readonly ILoggerFactory _loggerFactory;
     private readonly CountdownEvent _incomingRequestCounter = new(1);
     private bool? _isTrxEnabled;

src/Adapter/MSTest.TestAdapter/TestingPlatformAdapter/MSTestTestNodeConverter.cs

@@ -22,9 +22,9 @@ namespace Microsoft.VisualStudio.TestTools.UnitTesting;
 /// VSTest object model (<c>TestCase</c>/<c>TestResult</c>) or the VSTest bridge.
 /// </summary>
 /// <remarks>
-/// This mirrors, field-for-field, the mapping that the bridge performs today in
+/// This mirrors, field-for-field, the mapping that the VSTest bridge performed in
 /// <c>ObjectModelConverters.ToTestNode</c> (combined with <c>UnitTestElementExtensions.ToTestCase</c>,
-/// <c>TestResultExtensions.ToTestResult</c> and <c>MSTestBridgedTestFramework.AddAdditionalProperties</c>), so
+/// <c>TestResultExtensions.ToTestResult</c> and the bridge's <c>AddAdditionalProperties</c>), so
 /// switching MSTest to a native Microsoft.Testing.Platform integration produces identical <see cref="TestNode"/>s.
 /// MSTest does not use the <c>vstestProvider</c> named-feature capability, so the VSTest provider properties the
 /// bridge conditionally emits are intentionally not reproduced here.
@@ -133,7 +133,7 @@ private static void AddCategoriesAndTraits(TestNode testNode, UnitTestElement el
     private static void AddTestMethodIdentifier(TestNode testNode, TestMethod testMethod)
     {
         // NOTE: ManagedMethodName, in case of MSTest, carries the parameter types, so we prefer it to display the
-        // parameter types in Test Explorer. This mirrors MSTestBridgedTestFramework.AddAdditionalProperties.
+        // parameter types in Test Explorer. This mirrors what the VSTest bridge did in AddAdditionalProperties.
         if (!testMethod.HasManagedMethodAndTypeProperties)
         {
             return;

src/Adapter/MSTest.TestAdapter/TestingPlatformAdapter/BridgedConfiguration.cs → src/Adapter/MSTest.TestAdapter/TestingPlatformAdapter/PlatformServicesConfigurationAdapter.cs

@@ -9,11 +9,11 @@
 namespace Microsoft.VisualStudio.TestTools.UnitTesting;
 
 [SuppressMessage("ApiDesign", "RS0030:Do not use banned APIs", Justification = "We can use MTP from this folder")]
-internal sealed class BridgedConfiguration : PlatformServicesConfiguration
+internal sealed class PlatformServicesConfigurationAdapter : PlatformServicesConfiguration
 {
     private readonly IConfiguration _configuration;
 
-    public BridgedConfiguration(IConfiguration configuration)
+    public PlatformServicesConfigurationAdapter(IConfiguration configuration)
         => _configuration = configuration;
 
     public string? this[string key] => _configuration[key];

src/Adapter/MSTest.TestAdapter/TestingPlatformAdapter/TestApplicationBuilderExtensions.cs

@@ -3,7 +3,6 @@
 
 #if !WINDOWS_UWP
 using Microsoft.Testing.Extensions.TrxReport.Abstractions;
-using Microsoft.Testing.Extensions.VSTestBridge.Capabilities;
 using Microsoft.Testing.Platform.Builder;
 using Microsoft.Testing.Platform.Capabilities.TestFramework;
 using Microsoft.Testing.Platform.Helpers;
@@ -19,10 +18,9 @@ namespace Microsoft.VisualStudio.TestTools.UnitTesting;
 public static class TestApplicationBuilderExtensions
 {
     // NOTE: We intentionally do not use the bridge's VSTestBridgeExtensionBaseCapabilities because we don't want
-    // MSTest to use the vstestProvider capability. This implements BOTH the bridge's TRX capability interface (read
-    // by MSTestBridgedTestFramework, the current default) and MSTest's native one (read by MSTestTestFramework), so
-    // both frameworks observe the same TRX enablement.
-    private sealed class MSTestCapabilities : IInternalVSTestBridgeTrxReportCapability, IMSTestTrxReportCapability
+    // MSTest to use the vstestProvider capability. This implements MSTest's native TRX capability, read by
+    // MSTestTestFramework.
+    private sealed class MSTestCapabilities : IMSTestTrxReportCapability
     {
         public bool IsTrxEnabled { get; private set; }
 
@@ -56,19 +54,13 @@ public static void AddMSTest(this ITestApplicationBuilder testApplicationBuilder
         testApplicationBuilder.TestHostControllers.AddEnvironmentVariableProvider(serviceProvider
             => new MSTestRunSettingsEnvironmentVariableProvider(extension, serviceProvider.GetCommandLineOptions(), serviceProvider.GetFileSystem(), serviceProvider.GetEnvironment()));
 
-        // When the experimental native MTP integration is enabled, MSTest plugs into Microsoft.Testing.Platform
-        // directly (no VSTest bridge object model on the request path). Off by default, so shipping behavior is
-        // the bridged framework.
-        bool useNativeMtp = Environment.GetEnvironmentVariable("MSTEST_EXPERIMENTAL_NATIVE_MTP") is "1" or "true" or "True";
-
+        // MSTest plugs into Microsoft.Testing.Platform directly (no VSTest bridge object model on the request path).
         testApplicationBuilder.RegisterTestFramework(
             serviceProvider => new TestFrameworkCapabilities(
                 new MSTestCapabilities(),
                 new MSTestBannerCapability(serviceProvider.GetRequiredService<IPlatformInformation>()),
                 MSTestGracefulStopTestExecutionCapability.Instance),
-            (capabilities, serviceProvider) => useNativeMtp
-                ? new MSTestTestFramework(extension, getTestAssemblies, serviceProvider, capabilities)
-                : new MSTestBridgedTestFramework(extension, getTestAssemblies, serviceProvider, capabilities));
+            (capabilities, serviceProvider) => new MSTestTestFramework(extension, getTestAssemblies, serviceProvider, capabilities));
     }
 }
 #endif

src/Adapter/MSTest.TestAdapter/VSTestAdapter/MSTestDiscoverer.cs

@@ -26,7 +26,7 @@ internal sealed class MSTestDiscoverer : ITestDiscoverer
 
     // The parameterless constructor is required by VSTest, which instantiates the
     // discoverer via reflection. The internal constructor exists for tests and for the
-    // MTP bridge (MSTestBridgedTestFramework) which injects a telemetry sender.
+    // native Microsoft.Testing.Platform framework (MSTestTestFramework) which injects a telemetry sender.
     public MSTestDiscoverer()
         : this(new TestSourceHandler())
     {

test/IntegrationTests/MSTest.Acceptance.IntegrationTests/TestDiscoveryTests.cs

@@ -90,9 +90,8 @@ public async Task DiscoverTests_WithJsonOutput_ProducesValidJsonDocumentWithExpe
         }
 
         // Test1 should expose its TestMethodIdentifierProperty data, pinning every v1 schema field
-        // for that node from the outside. Note: MSTest's VSTestBridge currently leaves
-        // assemblyFullName and returnTypeFullName empty (TODO in MSTestBridgedTestFramework);
-        // assert presence only for those.
+        // for that node from the outside. MSTest currently leaves assemblyFullName and
+        // returnTypeFullName empty, so assert presence only for those.
         bool foundTest1WithType = false;
         for (int i = 0; i < tests.GetArrayLength(); i++)
         {