Fix parallel discovery

playground/TestPlatform.Playground/Program.cs

@@ -29,7 +29,7 @@ static void Main(string[] args)
         // copy of TestPlatform that is similar to what we ship.
         //
         // The copying might trigger only on re-build, if you see outdated dependencies, Rebuild this project instead of just Build.
-        // 
+        //
         // Use this as playground for your debugging of end-to-end scenarios, it will automatically attach vstest.console and teshost
         // sub-processes. It won't stop at entry-point automatically, don't forget to set your breakpoints, or remove VSTEST_DEBUG_NOBP
         // from the environment variables of this project.
@@ -51,6 +51,7 @@ static void Main(string[] args)
                 <RunSettings>
                     <RunConfiguration>
                         <InIsolation>true</InIsolation>
+                        <MaxCpuCount>0</MaxCpuCount>
                     </RunConfiguration>
                 </RunSettings>
             ";
@@ -62,6 +63,58 @@ static void Main(string[] args)
         r.RunTestsWithCustomTestHost(sources, sourceSettings, options, new TestRunHandler(), new DebuggerTestHostLauncher());
     }
 
+    public class PlaygroundTestDiscoveryHandler : ITestDiscoveryEventsHandler, ITestDiscoveryEventsHandler2
+    {
+        private int _testCasesCount;
+
+        public void HandleDiscoveredTests(IEnumerable<TestCase> discoveredTestCases)
+        {
+            Console.WriteLine($"[DISCOVERY.PROGRESS]");
+            Console.WriteLine(WriteTests(discoveredTestCases));
+            _testCasesCount += discoveredTestCases.Count();
+        }
+
+        public void HandleDiscoveryComplete(long totalTests, IEnumerable<TestCase> lastChunk, bool isAborted)
+        {
+            Console.WriteLine($"[DISCOVERY.COMPLETE] aborted? {isAborted}, tests count: {totalTests}");
+            Console.WriteLine("Last chunk:");
+            Console.WriteLine(WriteTests(lastChunk));
+        }
+
+        public void HandleDiscoveryComplete(DiscoveryCompleteEventArgs discoveryCompleteEventArgs, IEnumerable<TestCase> lastChunk)
+        {
+            Console.WriteLine($"[DISCOVERY.COMPLETE] aborted? {discoveryCompleteEventArgs.IsAborted}, tests count: {discoveryCompleteEventArgs.TotalCount}, discovered count: {_testCasesCount}");
+            Console.WriteLine("Last chunk:");
+            Console.WriteLine(WriteTests(lastChunk));
+            Console.WriteLine("Fully discovered:");
+            Console.WriteLine(WriteSources(discoveryCompleteEventArgs.FullyDiscoveredSources));
+            Console.WriteLine("Partially discovered:");
+            Console.WriteLine(WriteSources(discoveryCompleteEventArgs.PartiallyDiscoveredSources));
+            Console.WriteLine("Not discovered:");
+            Console.WriteLine(WriteSources(discoveryCompleteEventArgs.NotDiscoveredSources));
+        }
+
+        public void HandleLogMessage(TestMessageLevel level, string message)
+        {
+            Console.WriteLine($"[DISCOVERY.{level.ToString().ToUpper()}] {message}");
+        }
+
+        public void HandleRawMessage(string rawMessage)
+        {
+            Console.WriteLine($"[DISCOVERY.MESSAGE] {rawMessage}");
+        }
+
+        private static string WriteTests(IEnumerable<TestCase> testCases)
+            => testCases?.Any() == true
+                ? "\t" + string.Join("\n\t", testCases.Select(r => r.DisplayName))
+                : "\t<empty>";
+
+        private static string WriteSources(IEnumerable<string> sources)
+            => sources?.Any() == true
+                ? "\t" + string.Join("\n\t", sources)
+                : "\t<empty>";
+    }
+
     public class TestRunHandler : ITestRunEventsHandler
     {
 
@@ -76,33 +129,33 @@ public void HandleLogMessage(TestMessageLevel level, string message)
 
         public void HandleRawMessage(string rawMessage)
         {
-            Console.WriteLine($"[MESSAGE]: { rawMessage}");
+            Console.WriteLine($"[RUN.MESSAGE]: {rawMessage}");
         }
 
         public void HandleTestRunComplete(TestRunCompleteEventArgs testRunCompleteArgs, TestRunChangedEventArgs lastChunkArgs, ICollection<AttachmentSet> runContextAttachments, ICollection<string> executorUris)
         {
-            Console.WriteLine($"[COMPLETE]: err: { testRunCompleteArgs.Error }, lastChunk: {WriteTests(lastChunkArgs?.NewTestResults)}");
+            Console.WriteLine($"[RUN.COMPLETE]: err: {testRunCompleteArgs.Error}, lastChunk:");
+            Console.WriteLine(WriteTests(lastChunkArgs?.NewTestResults));
         }
 
         public void HandleTestRunStatsChange(TestRunChangedEventArgs testRunChangedArgs)
         {
-            Console.WriteLine($"[PROGRESS - NEW RESULTS]: {WriteTests(testRunChangedArgs.NewTestResults)}");
+            Console.WriteLine($"[RUN.PROGRESS]");
+            Console.WriteLine(WriteTests(testRunChangedArgs.NewTestResults));
         }
 
         public int LaunchProcessWithDebuggerAttached(TestProcessStartInfo testProcessStartInfo)
         {
             throw new NotImplementedException();
         }
 
-        private string WriteTests(IEnumerable<TestResult> testResults)
-        {
-            return WriteTests(testResults?.Select(t => t.TestCase));
-        }
+        private static string WriteTests(IEnumerable<TestResult> testResults)
+            => WriteTests(testResults?.Select(t => t.TestCase));
 
-        private string WriteTests(IEnumerable<TestCase> testCases)
-        {
-            return testCases == null ? null : "\t" + string.Join("\n\t", testCases.Select(r => r.DisplayName));
-        }
+        private static string WriteTests(IEnumerable<TestCase> testCases)
+            => testCases?.Any() == true
+                ? "\t" + string.Join("\n\t", testCases.Select(r => r.DisplayName))
+                : "\t<empty>";
     }
 
     internal class DebuggerTestHostLauncher : ITestHostLauncher2

src/Microsoft.TestPlatform.Common/Utilities/Debug.cs

@@ -0,0 +1,23 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics;
+
+using SystemDebug = System.Diagnostics.Debug;
+
+namespace Microsoft.TestPlatform;
+
+[SuppressMessage("ApiDesign", "RS0030:Do not used banned APIs", Justification = "Replacement API to allow nullable hints for compiler")]
+internal static class Debug
+{
+    /// <inheritdoc cref="SystemDebug.Assert(bool)"/>
+    [Conditional("DEBUG")]
+    public static void Assert([DoesNotReturnIf(false)] bool b)
+        => SystemDebug.Assert(b);
+
+    /// <inheritdoc cref="SystemDebug.Assert(bool, string)"/>
+    [Conditional("DEBUG")]
+    public static void Assert([DoesNotReturnIf(false)] bool b, string message)
+        => SystemDebug.Assert(b, message);
+}

src/Microsoft.TestPlatform.CommunicationUtilities/TestRequestSender.cs

@@ -572,20 +572,21 @@ private void OnDiscoveryMessageReceived(ITestDiscoveryEventsHandler2 discoveryEv
                     discoveryEventsHandler.HandleDiscoveredTests(testCases);
                     break;
                 case MessageType.DiscoveryComplete:
-                    var discoveryCompletePayload =
-                        _dataSerializer.DeserializePayload<DiscoveryCompletePayload>(data);
-                    var discoveryCompleteEventArgs = new DiscoveryCompleteEventArgs(
-                        discoveryCompletePayload.TotalTests,
-                        discoveryCompletePayload.IsAborted,
-                        discoveryCompletePayload.FullyDiscoveredSources,
-                        discoveryCompletePayload.PartiallyDiscoveredSources,
-                        discoveryCompletePayload.NotDiscoveredSources,
-                        discoveryCompletePayload.DiscoveredExtensions);
-
-                    discoveryCompleteEventArgs.Metrics = discoveryCompletePayload.Metrics;
+                    var payload = _dataSerializer.DeserializePayload<DiscoveryCompletePayload>(data);
+                    var discoveryCompleteEventArgs = new DiscoveryCompleteEventArgs
+                    {
+                        TotalCount = payload.TotalTests,
+                        IsAborted = payload.IsAborted,
+                        FullyDiscoveredSources = payload.FullyDiscoveredSources,
+                        PartiallyDiscoveredSources = payload.PartiallyDiscoveredSources,
+                        NotDiscoveredSources = payload.NotDiscoveredSources,
+                        DiscoveredExtensions = payload.DiscoveredExtensions,
+                    };
+
+                    discoveryCompleteEventArgs.Metrics = payload.Metrics;
                     discoveryEventsHandler.HandleDiscoveryComplete(
                         discoveryCompleteEventArgs,
-                        discoveryCompletePayload.LastDiscoveredTests);
+                        payload.LastDiscoveredTests);
                     SetOperationComplete();
                     break;
                 case MessageType.TestMessage: