Add ObserveException extension methods for Task and Task<T>

PowerKit.Tests/Extensions/TaskExtensionsTests.cs

@@ -0,0 +1,76 @@
+using System;
+using System.Threading.Tasks;
+using FluentAssertions;
+using PowerKit.Extensions;
+using Xunit;
+
+namespace PowerKit.Tests.Extensions;
+
+public class TaskExtensionsTests
+{
+    [Fact]
+    public async Task ObserveException_ReturnsFaultException_Test()
+    {
+        // Arrange
+        var task = Task.Run(() => throw new InvalidOperationException("test error"));
+
+        // Act
+        var exception = await task.ObserveException();
+
+        // Assert
+        task.IsFaulted.Should().BeTrue();
+        exception.Should().NotBeNull();
+        exception!.InnerException.Should().BeOfType<InvalidOperationException>();
+    }
+
+    [Fact]
+    public async Task ObserveException_SuccessfulTask_ReturnsNull_Test()
+    {
+        // Arrange
+        var task = Task.CompletedTask;
+
+        // Act
+        var exception = await task.ObserveException();
+
+        // Assert
+        task.IsCompletedSuccessfully.Should().BeTrue();
+        exception.Should().BeNull();
+    }
+
+    [Fact]
+    public async Task ObserveException_DoesNotRaiseUnobservedTaskException_Test()
+    {
+        // Arrange
+        var unobservedRaised = false;
+
+        EventHandler<UnobservedTaskExceptionEventArgs> handler = (_, e) =>
+        {
+            if (e.Exception.InnerException is InvalidOperationException { Message: "test error" })
+                unobservedRaised = true;
+
+            e.SetObserved();
+        };
+
+        TaskScheduler.UnobservedTaskException += handler;
+
+        try
+        {
+            // Act
+            _ = Task.Run(() => throw new InvalidOperationException("test error"))
+                .ObserveException();
+
+            await Task.Delay(50);
+
+            GC.Collect();
+            GC.WaitForPendingFinalizers();
+            GC.Collect();
+
+            // Assert
+            unobservedRaised.Should().BeFalse();
+        }
+        finally
+        {
+            TaskScheduler.UnobservedTaskException -= handler;
+        }
+    }
+}

PowerKit/Extensions/TaskExtensions.cs

@@ -0,0 +1,30 @@
+#if !NETFRAMEWORK || NET45_OR_GREATER
+using System;
+using System.Threading.Tasks;
+
+namespace PowerKit.Extensions;
+
+/// <summary>
+/// Extensions for <see cref="Task" />.
+/// </summary>
+public static class TaskExtensions
+{
+    extension(Task task)
+    {
+        /// <summary>
+        /// Registers a continuation that observes and suppresses the task's exception,
+        /// preventing it from surfacing as an unobserved task exception.
+        /// Returns a <see cref="Task{TResult}" /> that resolves to the observed
+        /// <see cref="AggregateException" />, or <see langword="null" /> if the task did not fault.
+        /// Intended for use on detached (fire-and-forget) tasks.
+        /// </summary>
+        public Task<AggregateException?> ObserveException() =>
+            task.ContinueWith(
+                static t => t.Exception,
+                default,
+                TaskContinuationOptions.ExecuteSynchronously,
+                TaskScheduler.Default
+            );
+    }
+}
+#endif