Add TestFailingCompletionHandlerCrashesProcess Test

src/Tests/TestComponentCSharp/Class.cpp

@@ -1213,6 +1213,14 @@ namespace winrt::TestComponentCSharp::implementation
         winrt::check_hresult(_asyncResult);
     }
 
+    void Class::SetFailingCompletedHandler(IAsyncAction const& action)
+    {
+        action.Completed([](IAsyncAction const&, AsyncStatus)
+        {
+            throw winrt::hresult_error(E_FAIL, L"Intentional failure in completion handler");
+        });
+    }
+
     IAsyncActionWithProgress<int32_t> Class::DoitAsyncWithProgress()
     {
         _asyncResult = E_PENDING;

src/Tests/TestComponentCSharp/Class.h

@@ -351,6 +351,8 @@ namespace winrt::TestComponentCSharp::implementation
         Windows::Foundation::IAsyncOperation<int32_t> AddAsync(int32_t lhs, int32_t rhs);
         Windows::Foundation::IAsyncOperationWithProgress<int32_t, int32_t> AddAsyncWithProgress(int32_t lhs, int32_t rhs);
 
+        void SetFailingCompletedHandler(Windows::Foundation::IAsyncAction const& action);
+
         Windows::Foundation::Point PointProperty();
         void PointProperty(Windows::Foundation::Point const& value);
         Windows::Foundation::Rect RectProperty();

src/Tests/TestComponentCSharp/TestComponentCSharp.idl

@@ -429,6 +429,8 @@ namespace TestComponentCSharp
         Windows.Foundation.IAsyncOperation<Int32> AddAsync(Int32 lhs, Int32 rhs);
         Windows.Foundation.IAsyncOperationWithProgress<Int32, Int32> AddAsyncWithProgress(Int32 lhs, Int32 rhs);
 
+        void SetFailingCompletedHandler(Windows.Foundation.IAsyncAction action);
+
         // Type mappings
         // "Simple" structs (blittable with changes to add properties/functions/constructors/etc.)
         Windows.Foundation.Point PointProperty;

src/Tests/UnitTest/TestComponentCSharp_Tests.cs

@@ -4092,5 +4092,24 @@ public void TestNontProjectedClassAsBaseClass()
             // Non projected class changes the behavior of the Value property to double it.
             Assert.AreEqual(6, customEquals.Value);
         }
+
+        [TestMethod]
+        public async Task TestFailingCompletionHandlerCrashesProcess()
+        {
+            // Create an IAsyncAction from a C# task that completes after 2 seconds.
+            var asyncAction = AsyncInfo.Run(_ => Task.Delay(TimeSpan.FromSeconds(2)));
+
+            // Pass it to native code which sets a Completed handler that throws.
+            var instance = new Class();
+            instance.SetFailingCompletedHandler(asyncAction);
+
+            // Wait long enough for the async action to complete and the native
+            // completion handler to fire. If the throwing handler crashes the
+            // process, we will never reach the assertion below.
+            await Task.Delay(TimeSpan.FromSeconds(5));
+
+            // If we get here, the process survived the throwing completion handler.
+            Assert.IsTrue(true, "Process survived the throwing native completion handler.");
+        }
     }
 }