Fix: Improve InfiniFrameWebViewManager closing message handling and add unit tests for SendMessage after disposal

src/InfiniFrame.BlazorWebView/InfiniFrameWebViewManager.cs

@@ -229,9 +229,8 @@ protected override void NavigateCore(Uri absoluteUri) {
     }
 
     protected override void SendMessage(string message) {
-        while (!_channel.Writer.TryWrite(message)) {
-            Thread.Sleep(200);
-        }
+        if (_channel.Writer.TryWrite(message)) return;
+        LazyLogger.Value?.LogDebug("Skipping WebView message because the message channel is closed.");
     }
 
     private async Task MessagePump() {
@@ -253,20 +252,23 @@ private async Task MessagePump() {
     }
 
     protected override async ValueTask DisposeAsyncCore() {
-        try { _channel.Writer.Complete(); }
-        catch (ChannelClosedException ex) {
-            LazyLogger.Value?.LogDebug(ex, "Channel was already closed during dispose.");
-        }
-
         try {
-            await _messagePumpTask.WaitAsync(TimeSpan.FromSeconds(5));
-        }
-        catch (TimeoutException) {
-            LazyLogger.Value?.LogWarning(
-                "Timed out while waiting for WebView message pump shutdown.");
+            await base.DisposeAsyncCore();
         }
+        finally {
+            try { _channel.Writer.Complete(); }
+            catch (ChannelClosedException ex) {
+                LazyLogger.Value?.LogDebug(ex, "Channel was already closed during dispose.");
+            }
 
-        await base.DisposeAsyncCore();
+            try {
+                await _messagePumpTask.WaitAsync(TimeSpan.FromSeconds(5));
+            }
+            catch (TimeoutException) {
+                LazyLogger.Value?.LogWarning(
+                    "Timed out while waiting for WebView message pump shutdown.");
+            }
+        }
     }
 
     private static bool IsNonFatalException(Exception exception)

tests/InfiniFrameTests.BlazorWebView/InfiniFrameWebViewManagerTests.cs

@@ -0,0 +1,62 @@
+// ---------------------------------------------------------------------------------------------------------------------
+// Imports
+// ---------------------------------------------------------------------------------------------------------------------
+using InfiniFrame;
+using InfiniFrame.BlazorWebView;
+using InfiniFrameTests.Shared;
+using Microsoft.AspNetCore.Components;
+using Microsoft.AspNetCore.Components.Web;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.FileProviders;
+using Microsoft.Extensions.Options;
+using NSubstitute;
+
+namespace InfiniFrameTests.BlazorWebView;
+
+// ---------------------------------------------------------------------------------------------------------------------
+// Code
+// ---------------------------------------------------------------------------------------------------------------------
+public class InfiniFrameWebViewManagerTests {
+    private sealed class TestableInfiniFrameWebViewManager(
+        IInfiniFrameWindowBuilder builder,
+        IServiceProvider provider,
+        Dispatcher dispatcher,
+        IFileProvider fileProvider,
+        JSComponentConfigurationStore jsComponents,
+        IOptions<InfiniFrameBlazorAppConfiguration> config
+    ) : InfiniFrameWebViewManager(builder, provider, dispatcher, fileProvider, jsComponents, config) {
+        public void SendMessageForTest(string message) => SendMessage(message);
+    }
+
+    [Test]
+    [Timeout(TimeoutUtility.DefaultTimeout)]
+    public async Task SendMessage_AfterDispose_ShouldReturnPromptly(CancellationToken ct) {
+        // Arrange
+        IInfiniFrameWindow window = Substitute.For<IInfiniFrameWindow>();
+        window.SendWebMessageAsync(Arg.Any<string>(), Arg.Any<CancellationToken>())
+            .Returns(Task.CompletedTask);
+
+        await using ServiceProvider provider = new ServiceCollection()
+            .AddLogging()
+            .AddSingleton(window)
+            .BuildServiceProvider();
+
+        var dispatcher = Substitute.For<Dispatcher>();
+        var manager = new TestableInfiniFrameWebViewManager(
+            InfiniFrameWindowBuilder.Create(),
+            provider,
+            dispatcher,
+            new NullFileProvider(),
+            new JSComponentConfigurationStore(),
+            Options.Create(new InfiniFrameBlazorAppConfiguration()));
+
+        await manager.DisposeAsync();
+
+        // Act
+        Task sendTask = Task.Run(() => manager.SendMessageForTest("late-dispose-message"), ct);
+
+        // Assert
+        await sendTask.WaitAsync(TimeSpan.FromSeconds(1), ct);
+        await window.DidNotReceive().SendWebMessageAsync("late-dispose-message", Arg.Any<CancellationToken>());
+    }
+}