feat: Misc fixes and enhancement to allow uno to use runtime test engine

src/TestApp/winui/Uno.UI.RuntimeTests.Engine.Skia.Gtk/Program.cs

@@ -4,7 +4,7 @@
 
 namespace Uno.UI.RuntimeTests.Engine.Skia.Gtk;
 
-internal class Program
+internal sealed class Program
 {
 	static void Main(string[] args)
 	{

src/Uno.UI.RuntimeTests.Engine.Library/Engine/ExternalRunner/RuntimeTestEmbeddedRunner.cs

@@ -10,6 +10,7 @@
 #endif
 
 using System;
+using System.Diagnostics;
 using System.IO;
 using System.Linq;
 using System.Runtime.CompilerServices;
@@ -49,9 +50,13 @@ private enum TestResultKind
 #pragma warning restore CA2255
 	public static void AutoStartTests()
 	{
+		Trace("Initializing runtime-tests module.");
+
 		if (Environment.GetEnvironmentVariable("UNO_RUNTIME_TESTS_RUN_TESTS") is { } testsConfig
 			&& Environment.GetEnvironmentVariable("UNO_RUNTIME_TESTS_OUTPUT_PATH") is { } outputPath)
 		{
+			Trace($"Application configured to start runtime-tests (Output={outputPath} | Config={testsConfig}).");
+
 			var outputKind = Enum.TryParse<TestResultKind>(Environment.GetEnvironmentVariable("UNO_RUNTIME_TESTS_OUTPUT_KIND"), ignoreCase: true, out var kind)
 				? kind
 				: TestResultKind.NUnit;
@@ -65,6 +70,10 @@ public static void AutoStartTests()
 
 			_ = RunTestsAndExit(testsConfig, outputPath, outputKind, isSecondaryApp);
 		}
+		else
+		{
+			Trace("Application has not been configured to start runtime-test, aborting runtime-test embedded runner.");
+		}
 	}
 
 	private static async Task RunTestsAndExit(string testsConfigRaw, string outputPath, TestResultKind outputKind, bool isSecondaryApp)
@@ -73,7 +82,7 @@ private static async Task RunTestsAndExit(string testsConfigRaw, string outputPa
 
 		try
 		{
-			Log("Waiting for app to init before running runtime-tests");
+			Log("Waiting for app to init before running runtime-tests.");
 
 #pragma warning disable CA1416 // Validate platform compatibility
 			Console.CancelKeyPress += (_, _) => ct.Cancel(true);
@@ -92,6 +101,8 @@ private static async Task RunTestsAndExit(string testsConfigRaw, string outputPa
 				throw new InvalidOperationException("Window.Current is null or does not have any valid dispatcher");
 			}
 
+			Trace("Got window (and dispatcher), continuing runtime-test initialization on it.");
+
 			// While the app init, parse the tests config
 			var config = default(UnitTestEngineConfig?);
 			if (testsConfigRaw.StartsWith('{'))
@@ -114,6 +125,8 @@ await window
 					{
 						try
 						{
+							Trace("Got dispatcher access, init the runtime-test engine.");
+
 							await RunTests(window, config, outputPath, outputKind, isSecondaryApp, ct.Token);
 							tcs.TrySetResult();
 						}
@@ -158,7 +171,7 @@ private static async Task RunTests(Window window, UnitTestEngineConfig config, s
 		}
 
 		// Then override the app content by the test control
-		Log("Initializing runtime-tests engine.");
+		Trace("Initializing runtime-tests engine.");
 		var engine = new UnitTestsControl { IsSecondaryApp = isSecondaryApp };
 		Window.Current.Content = engine;
 		await UIHelper.WaitForLoaded(engine, ct);
@@ -171,7 +184,7 @@ private static async Task RunTests(Window window, UnitTestEngineConfig config, s
 		Log($"Saving runtime-tests results to {outputPath}.");
 		switch (outputKind)
 		{
-			case TestResultKind.UnoRuntimeTests: 
+			case TestResultKind.UnoRuntimeTests:
 				await File.WriteAllTextAsync(outputPath, JsonSerializer.Serialize(engine.Results), Encoding.UTF8, ct);
 				break;
 
@@ -182,6 +195,10 @@ private static async Task RunTests(Window window, UnitTestEngineConfig config, s
 		}
 	}
 
+	[Conditional("DEBUG")]
+	private static void Trace(string text)
+		=> Console.WriteLine(text);
+
 	private static void Log(string text)
 		=> Console.WriteLine(text);
 

src/Uno.UI.RuntimeTests.Engine.Library/Engine/ExternalRunner/_Private/DevServer.cs

@@ -1,4 +1,8 @@
-#if !UNO_RUNTIMETESTS_DISABLE_UI && HAS_UNO_WINUI // HAS_UNO_WINUI: exclude non net7 platforms
+using System;
+using System.ComponentModel;
+using System.IO;
+
+#if !UNO_RUNTIMETESTS_DISABLE_UI && HAS_UNO_WINUI // HAS_UNO_WINUI: exclude non net7 platforms
 #nullable enable
 
 #if !IS_UNO_RUNTIMETEST_PROJECT
@@ -18,17 +22,37 @@ namespace Uno.UI.RuntimeTests.Internal.Helpers;
 [global::System.Runtime.Versioning.SupportedOSPlatform("windows")]
 [global::System.Runtime.Versioning.SupportedOSPlatform("linux")]
 [global::System.Runtime.Versioning.SupportedOSPlatform("freeBSD")]
-internal sealed partial class DevServer : global::System.IAsyncDisposable
+public sealed partial class DevServer : global::System.IAsyncDisposable
 {
 	private static readonly global::Microsoft.Extensions.Logging.ILogger _log = global::Uno.Extensions.LogExtensionPoint.Log(typeof(DevServer));
 	private static int _instance;
 	private static string? _devServerPath;
 
+	/// <summary>
+	/// Sets path to the dev-server host assembly (i.e. the Uno.UI.RemoteControl.Host.dll file).
+	/// </summary>
+	/// <param name="path">Path for the dev-server host assembly.</param>
+	[EditorBrowsable(EditorBrowsableState.Advanced)] // To be used by uno only
+	public static void SetDefaultPath(string path)
+		=> _devServerPath = path;
+
+	/// <summary>
+	/// Starts a new dev server instance
+	/// </summary>
+	/// <param name="ct">Cancellation token to abort the initialization of the server.</param>
+	/// <returns>The new dev server instance.</returns>
+	public static async global::System.Threading.Tasks.Task<DevServer> Start(string path, global::System.Threading.CancellationToken ct)
+		=> StartCore(path, GetTcpPort());
+
 	/// <summary>
 	/// Starts a new dev server instance
 	/// </summary>
 	/// <param name="ct">Cancellation token to abort the initialization of the server.</param>
 	/// <returns>The new dev server instance.</returns>
+	/// <remarks>
+	/// The path of the dev-server will be resolved from the UNO_RUNTIME_TESTS_DEV_SERVER_PATH environment variable (path to the Uno.UI.RemoteControl.Host.dll file),
+	/// and if not defined, it the latest version version will be pulled from NuGet.
+	/// </remarks>
 	public static async global::System.Threading.Tasks.Task<DevServer> Start(global::System.Threading.CancellationToken ct)
 	{
 #if !HAS_UNO_DEVSERVER
@@ -55,7 +79,7 @@ private DevServer(global::System.Diagnostics.Process process, int port)
 	public int Port { get; }
 
 	private static async global::System.Threading.Tasks.Task<string> GetDevServer(global::System.Threading.CancellationToken ct)
-		=> _devServerPath ??= await PullDevServer(ct);
+		=> _devServerPath ??= Environment.GetEnvironmentVariable("UNO_RUNTIME_TESTS_DEV_SERVER_PATH") is { Length: > 0 } path ? path : await PullDevServer(ct);
 
 	/// <summary>
 	/// Pulls the latest version of dev server from NuGet and returns the path to the executable

src/Uno.UI.RuntimeTests.Engine.Library/Engine/UnitTestFilter.cs

@@ -48,15 +48,20 @@ private static IUnitTestEngineFilter Parse(string? syntax)
 		}
 		else
 		{
-			var index = 0;
+			int previousIndex, index = 0;
 			var pending = default(IUnitTestEngineFilter?);
 			var stx = syntax.AsSpan();
 			do
 			{
-				pending = ReadToken(pending, ref index, stx);
-			} while (index < syntax.Length);
+				previousIndex = index;
+				var token = ReadToken(pending, ref index, stx);
+				if (token is not NullFilter)
+				{
+					pending = token; // Avoids to override the current parsed filter is something went wrong
+				}
+			} while (index < syntax.Length && index > previousIndex);
 
-			return pending;
+			return pending ?? new NullFilter();
 		}
 	}
 

src/Uno.UI.RuntimeTests.Engine.Library/Library/Helpers/HotReloadHelper.DevServer.cs

@@ -31,7 +31,7 @@ static partial void TryUseDevServerFileUpdater()
 	partial record FileEdit
 	{
 		public UpdateFile ToMessage()
-			=> new UpdateFile
+			=> new()
 			{
 				FilePath = FilePath,
 				OldText = OldText,
@@ -48,28 +48,28 @@ public async ValueTask EnsureReady(CancellationToken ct)
 
 			if (RemoteControlClient.Instance is null)
 			{
-				throw new InvalidOperationException("Dev server is not available.");
+				throw new InvalidOperationException("Dev server is not available (make sure to reference the Uno.WinUI.DevServer package).");
 			}
 
 			if (RemoteControlClient.Instance.Processors.OfType<ClientHotReloadProcessor>().FirstOrDefault() is not { } hotReload)
 			{
-				throw new InvalidOperationException("App is not configured to accept hot-reload.");
+				throw new InvalidOperationException("App is not configured to accept hot-reload (project has to be build in debug to get processor path injected).");
 			}
 
-			var timeout = Task.Delay(ConnectionTimeout, ct);
+			var timeout = Task.Delay(DefaultConnectionTimeout, ct);
 			if (await Task.WhenAny(timeout, RemoteControlClient.Instance.WaitForConnection(ct)) == timeout)
 			{
 				throw new TimeoutException(
 					"Timeout while waiting for the app to connect to the dev-server. "
-					+ "This usually indicates that the dev-server is not running on the expected combination of hots and port"
+					+ "This usually indicates that the dev-server is not running on the expected combination of host and port"
 					+ "(For runtime-tests run in secondary app instance, the server should be listening for connection on "
 					+ $"{Environment.GetEnvironmentVariable("UNO_DEV_SERVER_HOST")}:{Environment.GetEnvironmentVariable("UNO_DEV_SERVER_PORT")}).");
 			}
 
 			_log.LogTrace("Client connected, waiting for dev-server to load the workspace (i.e. initializing roslyn with the solution) ...");
 
 			var hotReloadReady = hotReload.WaitForWorkspaceLoaded(ct);
-			timeout = Task.Delay(WorkspaceTimeout, ct);
+			timeout = Task.Delay(DefaultWorkspaceTimeout, ct);
 			if (await Task.WhenAny(timeout, hotReloadReady) == timeout)
 			{
 				throw new TimeoutException(

src/Uno.UI.RuntimeTests.Engine.Library/Library/Helpers/HotReloadHelper.cs

@@ -63,14 +63,20 @@ public interface IFileUpdater
 	private static readonly global::Microsoft.Extensions.Logging.ILogger _log = typeof(HotReloadHelper).Log();
 	private static IFileUpdater _impl = new NotSupported();
 
-	// The delay for the client to connect to the dev-server
-	private static global::System.TimeSpan ConnectionTimeout = global::System.TimeSpan.FromSeconds(3);
+	/// <summary>
+	/// The delay for the client to connect to the dev-server
+	/// </summary>
+	public static global::System.TimeSpan DefaultConnectionTimeout = global::System.TimeSpan.FromSeconds(3);
 
-	// The delay for the server to load the workspace and let the client know it's ready
-	private static global::System.TimeSpan WorkspaceTimeout = global::System.TimeSpan.FromSeconds(30);
+	/// <summary>
+	/// The delay for the server to load the workspace and let the client know it's ready
+	/// </summary>
+	public static global::System.TimeSpan DefaultWorkspaceTimeout = global::System.TimeSpan.FromSeconds(30);
 
-	// The delay for the server to send metadata update once a file has been modified
-	private static global::System.TimeSpan MetadataUpdateTimeout = global::System.TimeSpan.FromSeconds(5);
+	/// <summary>
+	/// The delay for the server to send metadata update once a file has been modified
+	/// </summary>
+	public static global::System.TimeSpan DefaultMetadataUpdateTimeout = global::System.TimeSpan.FromSeconds(5);
 
 	static HotReloadHelper()
 	{
@@ -227,7 +233,7 @@ public static FileEdit CreateFileEdit(
 
 				_log.LogTrace("File edition requested, waiting for metadata update (i.e. the code changes to be applied in the current app) ...");
 
-				var timeout = global::System.Threading.Tasks.Task.Delay(MetadataUpdateTimeout, ct);
+				var timeout = global::System.Threading.Tasks.Task.Delay(DefaultMetadataUpdateTimeout, ct);
 				if (await global::System.Threading.Tasks.Task.WhenAny(timeout, cts.Task) == timeout)
 				{
 					throw new global::System.TimeoutException(