Use fakes to surround vstest core and test it

TestPlatform.sln

@@ -179,6 +179,12 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MSTest1", "playground\MSTes
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "AttachmentProcessorDataCollector", "test\TestAssets\AttachmentProcessorDataCollector\AttachmentProcessorDataCollector.csproj", "{B6AF6BCD-64C6-4F4E-ABCA-C8AA2AA66B7B}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "vstest.ProgrammerTests", "test\vstest.ProgrammerTests\vstest.ProgrammerTests.csproj", "{B1F84FD8-6150-4ECA-9AD7-C316E04E17D8}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Intent", "test\Intent\Intent.csproj", "{BFBB35C9-6437-480A-8DCC-AE3700110E7D}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Intent.Primitives", "test\Intent.Primitives\Intent.Primitives.csproj", "{29270853-90DC-4C39-9621-F47AE40A79B6}"
+EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "testhost.arm64", "src\testhost.arm64\testhost.arm64.csproj", "{186069FE-E1E8-4DE1-BEA4-0FF1484D22D1}"
 EndProject
 Global
@@ -883,6 +889,42 @@ Global
 		{B6AF6BCD-64C6-4F4E-ABCA-C8AA2AA66B7B}.Release|x64.Build.0 = Release|Any CPU
 		{B6AF6BCD-64C6-4F4E-ABCA-C8AA2AA66B7B}.Release|x86.ActiveCfg = Release|Any CPU
 		{B6AF6BCD-64C6-4F4E-ABCA-C8AA2AA66B7B}.Release|x86.Build.0 = Release|Any CPU
+		{B1F84FD8-6150-4ECA-9AD7-C316E04E17D8}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{B1F84FD8-6150-4ECA-9AD7-C316E04E17D8}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{B1F84FD8-6150-4ECA-9AD7-C316E04E17D8}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{B1F84FD8-6150-4ECA-9AD7-C316E04E17D8}.Debug|x64.Build.0 = Debug|Any CPU
+		{B1F84FD8-6150-4ECA-9AD7-C316E04E17D8}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{B1F84FD8-6150-4ECA-9AD7-C316E04E17D8}.Debug|x86.Build.0 = Debug|Any CPU
+		{B1F84FD8-6150-4ECA-9AD7-C316E04E17D8}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{B1F84FD8-6150-4ECA-9AD7-C316E04E17D8}.Release|Any CPU.Build.0 = Release|Any CPU
+		{B1F84FD8-6150-4ECA-9AD7-C316E04E17D8}.Release|x64.ActiveCfg = Release|Any CPU
+		{B1F84FD8-6150-4ECA-9AD7-C316E04E17D8}.Release|x64.Build.0 = Release|Any CPU
+		{B1F84FD8-6150-4ECA-9AD7-C316E04E17D8}.Release|x86.ActiveCfg = Release|Any CPU
+		{B1F84FD8-6150-4ECA-9AD7-C316E04E17D8}.Release|x86.Build.0 = Release|Any CPU
+		{BFBB35C9-6437-480A-8DCC-AE3700110E7D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{BFBB35C9-6437-480A-8DCC-AE3700110E7D}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{BFBB35C9-6437-480A-8DCC-AE3700110E7D}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{BFBB35C9-6437-480A-8DCC-AE3700110E7D}.Debug|x64.Build.0 = Debug|Any CPU
+		{BFBB35C9-6437-480A-8DCC-AE3700110E7D}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{BFBB35C9-6437-480A-8DCC-AE3700110E7D}.Debug|x86.Build.0 = Debug|Any CPU
+		{BFBB35C9-6437-480A-8DCC-AE3700110E7D}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{BFBB35C9-6437-480A-8DCC-AE3700110E7D}.Release|Any CPU.Build.0 = Release|Any CPU
+		{BFBB35C9-6437-480A-8DCC-AE3700110E7D}.Release|x64.ActiveCfg = Release|Any CPU
+		{BFBB35C9-6437-480A-8DCC-AE3700110E7D}.Release|x64.Build.0 = Release|Any CPU
+		{BFBB35C9-6437-480A-8DCC-AE3700110E7D}.Release|x86.ActiveCfg = Release|Any CPU
+		{BFBB35C9-6437-480A-8DCC-AE3700110E7D}.Release|x86.Build.0 = Release|Any CPU
+		{29270853-90DC-4C39-9621-F47AE40A79B6}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{29270853-90DC-4C39-9621-F47AE40A79B6}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{29270853-90DC-4C39-9621-F47AE40A79B6}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{29270853-90DC-4C39-9621-F47AE40A79B6}.Debug|x64.Build.0 = Debug|Any CPU
+		{29270853-90DC-4C39-9621-F47AE40A79B6}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{29270853-90DC-4C39-9621-F47AE40A79B6}.Debug|x86.Build.0 = Debug|Any CPU
+		{29270853-90DC-4C39-9621-F47AE40A79B6}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{29270853-90DC-4C39-9621-F47AE40A79B6}.Release|Any CPU.Build.0 = Release|Any CPU
+		{29270853-90DC-4C39-9621-F47AE40A79B6}.Release|x64.ActiveCfg = Release|Any CPU
+		{29270853-90DC-4C39-9621-F47AE40A79B6}.Release|x64.Build.0 = Release|Any CPU
+		{29270853-90DC-4C39-9621-F47AE40A79B6}.Release|x86.ActiveCfg = Release|Any CPU
+		{29270853-90DC-4C39-9621-F47AE40A79B6}.Release|x86.Build.0 = Release|Any CPU
 		{186069FE-E1E8-4DE1-BEA4-0FF1484D22D1}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{186069FE-E1E8-4DE1-BEA4-0FF1484D22D1}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{186069FE-E1E8-4DE1-BEA4-0FF1484D22D1}.Debug|x64.ActiveCfg = Debug|Any CPU
@@ -970,6 +1012,9 @@ Global
 		{545A88D3-1AE2-4D39-9B7C-C691768AD17F} = {6CE2F530-582B-4695-A209-41065E103426}
 		{57A61A09-10AD-44BE-8DF4-A6FD108F7DF7} = {6CE2F530-582B-4695-A209-41065E103426}
 		{B6AF6BCD-64C6-4F4E-ABCA-C8AA2AA66B7B} = {D9A30E32-D466-4EC5-B4F2-62E17562279B}
+		{B1F84FD8-6150-4ECA-9AD7-C316E04E17D8} = {B27FAFDF-2DBA-4AB0-BA85-FD5F21D359D6}
+		{BFBB35C9-6437-480A-8DCC-AE3700110E7D} = {B27FAFDF-2DBA-4AB0-BA85-FD5F21D359D6}
+		{29270853-90DC-4C39-9621-F47AE40A79B6} = {B27FAFDF-2DBA-4AB0-BA85-FD5F21D359D6}
 		{186069FE-E1E8-4DE1-BEA4-0FF1484D22D1} = {ED0C35EB-7F31-4841-A24F-8EB708FFA959}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution

src/Microsoft.TestPlatform.Client/Friends.cs

@@ -10,5 +10,6 @@
 #region Test Assemblies
 
 [assembly: InternalsVisibleTo("Microsoft.TestPlatform.Client.UnitTests, PublicKey=002400000480000094000000060200000024000052534131000400000100010007d1fa57c4aed9f0a32e84aa0faefd0de9e8fd6aec8f87fb03766c834c99921eb23be79ad9d5dcc1dd9ad236132102900b723cf980957fc4e177108fc607774f29e8320e92ea05ece4e821c0a5efe8f1645c4c0c93c1ab99285d622caa652c1dfad63d745d6f2de5f17e5eaf0fc4963d261c8a12436518206dc093344d5ad293")]
+[assembly: InternalsVisibleTo("vstest.ProgrammerTests, PublicKey=002400000480000094000000060200000024000052534131000400000100010007d1fa57c4aed9f0a32e84aa0faefd0de9e8fd6aec8f87fb03766c834c99921eb23be79ad9d5dcc1dd9ad236132102900b723cf980957fc4e177108fc607774f29e8320e92ea05ece4e821c0a5efe8f1645c4c0c93c1ab99285d622caa652c1dfad63d745d6f2de5f17e5eaf0fc4963d261c8a12436518206dc093344d5ad293")]
 
 #endregion

src/Microsoft.TestPlatform.Client/TestPlatform.cs

@@ -36,7 +36,7 @@ namespace Microsoft.VisualStudio.TestPlatform.Client;
 /// </summary>
 internal class TestPlatform : ITestPlatform
 {
-    private readonly TestRuntimeProviderManager _testHostProviderManager;
+    private readonly ITestRuntimeProviderManager _testHostProviderManager;
 
     private readonly IFileHelper _fileHelper;
 
@@ -66,10 +66,10 @@ public TestPlatform()
     /// <param name="testEngine">The test engine.</param>
     /// <param name="filehelper">The file helper.</param>
     /// <param name="testHostProviderManager">The data.</param>
-    protected TestPlatform(
+    protected internal TestPlatform(
         ITestEngine testEngine,
         IFileHelper filehelper,
-        TestRuntimeProviderManager testHostProviderManager)
+        ITestRuntimeProviderManager testHostProviderManager)
     {
         TestEngine = testEngine;
         _fileHelper = filehelper;
@@ -117,6 +117,11 @@ public ITestRunRequest CreateTestRunRequest(
         ITestLoggerManager loggerManager = TestEngine.GetLoggerManager(requestData);
         loggerManager.Initialize(testRunCriteria.TestRunSettings);
 
+        // TODO: PERF: this will create a testhost manager, and then it will pass that to GetExecutionManager, where it will
+        // be used only when we will run in-process. If we don't run in process, we will throw away the manager we just
+        // created and let the proxy parallel callbacks to create a new one. This seems to be very easy to move to the GetExecutionManager,
+        // and safe as well, so we create the manager only once.
+        // TODO: Of course TestEngine.GetExecutionManager is public api...
         ITestRuntimeProvider testHostManager = _testHostProviderManager.GetTestHostManagerByRunConfiguration(testRunCriteria.TestRunSettings);
         TestPlatform.ThrowExceptionIfTestHostManagerIsNull(testHostManager, testRunCriteria.TestRunSettings);
 

src/Microsoft.TestPlatform.Common/Friends.cs

@@ -25,4 +25,6 @@
 [assembly: InternalsVisibleTo("Microsoft.TestPlatform.Extensions.BlameDataCollector.UnitTests, PublicKey=002400000480000094000000060200000024000052534131000400000100010007d1fa57c4aed9f0a32e84aa0faefd0de9e8fd6aec8f87fb03766c834c99921eb23be79ad9d5dcc1dd9ad236132102900b723cf980957fc4e177108fc607774f29e8320e92ea05ece4e821c0a5efe8f1645c4c0c93c1ab99285d622caa652c1dfad63d745d6f2de5f17e5eaf0fc4963d261c8a12436518206dc093344d5ad293")]
 [assembly: InternalsVisibleTo("Microsoft.TestPlatform.TestUtilities, PublicKey=002400000480000094000000060200000024000052534131000400000100010007d1fa57c4aed9f0a32e84aa0faefd0de9e8fd6aec8f87fb03766c834c99921eb23be79ad9d5dcc1dd9ad236132102900b723cf980957fc4e177108fc607774f29e8320e92ea05ece4e821c0a5efe8f1645c4c0c93c1ab99285d622caa652c1dfad63d745d6f2de5f17e5eaf0fc4963d261c8a12436518206dc093344d5ad293")]
 [assembly: InternalsVisibleTo("Microsoft.TestPlatform.AcceptanceTests, PublicKey=002400000480000094000000060200000024000052534131000400000100010007d1fa57c4aed9f0a32e84aa0faefd0de9e8fd6aec8f87fb03766c834c99921eb23be79ad9d5dcc1dd9ad236132102900b723cf980957fc4e177108fc607774f29e8320e92ea05ece4e821c0a5efe8f1645c4c0c93c1ab99285d622caa652c1dfad63d745d6f2de5f17e5eaf0fc4963d261c8a12436518206dc093344d5ad293")]
+[assembly: InternalsVisibleTo("vstest.ProgrammerTests, PublicKey=002400000480000094000000060200000024000052534131000400000100010007d1fa57c4aed9f0a32e84aa0faefd0de9e8fd6aec8f87fb03766c834c99921eb23be79ad9d5dcc1dd9ad236132102900b723cf980957fc4e177108fc607774f29e8320e92ea05ece4e821c0a5efe8f1645c4c0c93c1ab99285d622caa652c1dfad63d745d6f2de5f17e5eaf0fc4963d261c8a12436518206dc093344d5ad293")]
+
 #endregion

src/Microsoft.TestPlatform.Common/Hosting/ITestRuntimeProviderManager.cs

@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+namespace Microsoft.VisualStudio.TestPlatform.Common.Hosting;
+
+using Microsoft.VisualStudio.TestPlatform.ObjectModel.Host;
+
+internal interface ITestRuntimeProviderManager
+{
+    ITestRuntimeProvider GetTestHostManagerByRunConfiguration(string runConfiguration);
+    ITestRuntimeProvider GetTestHostManagerByUri(string hostUri);
+}

src/Microsoft.TestPlatform.Common/Hosting/TestRunTimeProviderManager.cs

@@ -14,7 +14,7 @@ namespace Microsoft.VisualStudio.TestPlatform.Common.Hosting;
 /// <summary>
 /// Responsible for managing TestRuntimeProviderManager extensions
 /// </summary>
-public class TestRuntimeProviderManager
+public class TestRuntimeProviderManager : ITestRuntimeProviderManager
 {
     private static TestRuntimeProviderManager s_testHostManager;
 

src/Microsoft.TestPlatform.CommunicationUtilities/DataCollectionRequestHandler.cs

@@ -152,6 +152,14 @@ public static DataCollectionRequestHandler Create(
     {
         ValidateArg.NotNull(communicationManager, nameof(communicationManager));
         ValidateArg.NotNull(messageSink, nameof(messageSink));
+        // TODO: The MessageSink and DataCollectionRequestHandler have circular dependency.
+        // Message sink is injected into this Create method and then into constructor
+        // and into the constructor of DataCollectionRequestHandler. Data collection manager
+        // is then assigned to .Instace (which unlike many other .Instance is not populated
+        // directly in that property, but is created here). And then MessageSink depends on
+        // the .Instance. This is a very complicated way of solving the circular dependency,
+        // and should be replaced by adding a property to Message and assigning it.
+        // .Instance can then be removed.
         if (Instance == null)
         {
             lock (SyncObject)

src/Microsoft.TestPlatform.CommunicationUtilities/Interfaces/Communication/ConnectedEventArgs.cs

@@ -15,6 +15,7 @@ public class ConnectedEventArgs : EventArgs
     /// <summary>
     /// Initializes a new instance of the <see cref="ConnectedEventArgs"/> class.
     /// </summary>
+    // TODO: Do we need this constructor?
     public ConnectedEventArgs()
     {
     }

src/Microsoft.TestPlatform.CommunicationUtilities/Interfaces/ICommunicationEndpoint.cs

@@ -15,7 +15,7 @@ public interface ICommunicationEndPoint
     event EventHandler<ConnectedEventArgs> Connected;
 
     /// <summary>
-    /// Event raised when an endPoint is disconnected.
+    /// Event raised when an endPoint is disconnected on failure. It should not be notified when we are just closing the connection after success.
     /// </summary>
     event EventHandler<DisconnectedEventArgs> Disconnected;
 

src/Microsoft.TestPlatform.CommunicationUtilities/Messages/Message.cs

@@ -21,6 +21,9 @@ public class Message
     /// <summary>
     /// Gets or sets the payload.
     /// </summary>
+    // TODO: Our public contract says that we should be able to communicate over JSON, but we should not be stopping ourselves from
+    // negotiating a different protocol. Or using a different serialization library than NewtonsoftJson. Check why this is published as JToken
+    // and not as a string.
     public JToken Payload { get; set; }
 
     /// <summary>
@@ -29,6 +32,8 @@ public class Message
     /// <returns> The <see cref="string"/>. </returns>
     public override string ToString()
     {
+        // TODO: Review where this is used, we should avoid extensive serialization and deserialization,
+        // and this might be happening in multiple places that are not the edge of our process.
         return "(" + MessageType + ") -> " + (Payload == null ? "null" : Payload.ToString(Formatting.Indented));
     }
 }

src/Microsoft.TestPlatform.CommunicationUtilities/SocketClient.cs

@@ -96,17 +96,17 @@ private void OnServerConnected(Task connectAsyncTask)
                 // Start the message loop
                 Task.Run(() => _tcpClient.MessageLoopAsync(
                         _channel,
-                        Stop,
+                        StopOnError,
                         _cancellation.Token))
                     .ConfigureAwait(false);
             }
         }
     }
 
-    private void Stop(Exception error)
+    private void StopOnError(Exception error)
     {
         EqtTrace.Info("SocketClient.PrivateStop: Stop communication from server endpoint: {0}, error:{1}", _endPoint, error);
-
+        // This is here to prevent stack overflow.
         if (!_stopped)
         {
             // Do not allow stop to be called multiple times.

src/Microsoft.TestPlatform.CommunicationUtilities/SocketServer.cs

@@ -102,11 +102,16 @@ private void OnClientConnected(TcpClient client)
             EqtTrace.Verbose("SocketServer.OnClientConnected: Client connected for endPoint: {0}, starting MessageLoopAsync:", _endPoint);
 
             // Start the message loop
-            Task.Run(() => _tcpClient.MessageLoopAsync(_channel, error => Stop(error), _cancellation.Token)).ConfigureAwait(false);
+            Task.Run(() => _tcpClient.MessageLoopAsync(_channel, error => StopOnError(error), _cancellation.Token)).ConfigureAwait(false);
         }
     }
 
-    private void Stop(Exception error)
+    /// <summary>
+    /// Stop the connection when error was encountered. Dispose all communication, and notify subscribers of Disconnected event
+    /// that we aborted.
+    /// </summary>
+    /// <param name="error"></param>
+    private void StopOnError(Exception error)
     {
         EqtTrace.Info("SocketServer.PrivateStop: Stopping server endPoint: {0} error: {1}", _endPoint, error);