add UnobservedTaskExceptionTest

src/csharp/Grpc.IntegrationTesting/UnobservedTaskExceptionTest.cs

@@ -0,0 +1,99 @@
+#region Copyright notice and license
+
+// Copyright 2019 The gRPC Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Grpc.Core;
+using Grpc.Core.Utils;
+using Grpc.Testing;
+using NUnit.Framework;
+
+namespace Grpc.IntegrationTesting
+{
+    /// <summary>
+    /// Runs interop tests in-process.
+    /// </summary>
+    public class UnobservedTaskExceptionTest
+    {
+        const string Host = "localhost";
+        Server server;
+        Channel channel;
+        TestService.TestServiceClient client;
+
+        [OneTimeSetUp]
+        public void Init()
+        {
+            // Disable SO_REUSEPORT to prevent https://github.com/grpc/grpc/issues/10755
+            server = new Server(new[] { new ChannelOption(ChannelOptions.SoReuseport, 0) })
+            {
+                Services = { TestService.BindService(new TestServiceImpl()) },
+                Ports = { { Host, ServerPort.PickUnused, ServerCredentials.Insecure } }
+            };
+            server.Start();
+
+            int port = server.Ports.Single().BoundPort;
+            channel = new Channel(Host, port, ChannelCredentials.Insecure);
+            client = new TestService.TestServiceClient(channel);
+        }
+
+        [OneTimeTearDown]
+        public void Cleanup()
+        {
+            channel.ShutdownAsync().Wait();
+            server.ShutdownAsync().Wait();
+        }
+
+        [Test]
+        public async Task NoUnobservedTaskExceptionForAbandonedStreamingResponse()
+        {
+            // Verify that https://github.com/grpc/grpc/issues/17458 has been fixed.
+            // Create a streaming response call, then cancel it without reading all the responses
+            // and check that no unobserved task exceptions have been thrown.
+
+            int unobservedTaskExceptionCounter = 0;
+
+            TaskScheduler.UnobservedTaskException += (sender, e) => {
+                unobservedTaskExceptionCounter++;
+                Console.WriteLine("Detected unobserved task exception: " + e.Exception);
+            };
+
+            var bodySizes = new List<int> { 10, 10, 10, 10, 10 };
+            var request = new StreamingOutputCallRequest {
+                ResponseParameters = { bodySizes.Select((size) => new ResponseParameters { Size = size }) }
+            };
+
+            for (int i = 0; i < 50; i++)
+            {
+                Console.WriteLine($"Starting iteration {i}");
+                using (var call = client.StreamingOutputCall(request))
+                {
+                    // Intentionally only read the first response (we know there's more)
+                    // The call will be cancelled as soon as we leave the "using" statement.
+                    var firstResponse = await call.ResponseStream.MoveNext();
+                }
+                // Make it more likely to trigger the "Unobserved task exception" warning
+                GC.Collect();
+            }
+
+            Assert.AreEqual(0, unobservedTaskExceptionCounter);
+        }
+    }
+}

src/csharp/tests.json

@@ -68,7 +68,8 @@
     "Grpc.IntegrationTesting.InteropClientServerTest",
     "Grpc.IntegrationTesting.MetadataCredentialsTest",
     "Grpc.IntegrationTesting.RunnerClientServerTest",
-    "Grpc.IntegrationTesting.SslCredentialsTest"
+    "Grpc.IntegrationTesting.SslCredentialsTest",
+    "Grpc.IntegrationTesting.UnobservedTaskExceptionTest"
   ],
   "Grpc.Reflection.Tests": [
     "Grpc.Reflection.Tests.ReflectionClientServerTest",