throw fewer exceptions during shutdown, and catch exceptions during shutdown in unit test framework

src/DurableTask.Netherite/Util/WorkItemQueue.cs

@@ -32,22 +32,31 @@ namespace DurableTask.Netherite
 
         public async ValueTask<T> GetNext(TimeSpan timeout, CancellationToken cancellationToken)
         {
-            T result = default;
-            bool success = await this.count.WaitAsync((int) timeout.TotalMilliseconds, cancellationToken);
-            if (success)
+            try
             {
-                success = this.work.TryDequeue(out result);
-            
-                // we should always succeed here; but just for the unlikely case that we don't 
-                // (e.g. if concurrent queue implementation is not linearizable),
-                // put the count back up by one if we didn't actually get an element
-                if (!success)
-                {
-                    this.count.Release();
-                }           
-            }
+                T result = default;
 
-            return result;
+                bool success = await this.count.WaitAsync((int)timeout.TotalMilliseconds, cancellationToken);
+
+                if (success)
+                {
+                    success = this.work.TryDequeue(out result);
+
+                    // we should always succeed here; but just for the unlikely case that we don't 
+                    // (e.g. if concurrent queue implementation is not linearizable),
+                    // put the count back up by one if we didn't actually get an element
+                    if (!success)
+                    {
+                        this.count.Release();
+                    }
+                }
+
+                return result;
+            }
+            catch (OperationCanceledException) when (cancellationToken.IsCancellationRequested)
+            {
+                return default(T);
+            }
         }
     }
 }

test/DurableTask.Netherite.AzureFunctions.Tests/IntegrationTestBase.cs

@@ -52,9 +52,22 @@ namespace DurableTask.Netherite.AzureFunctions.Tests
             this.AddFunctions(typeof(ClientFunctions));
         }
 
-        Task IAsyncLifetime.InitializeAsync() => this.functionsHost.StartAsync();
+        async Task IAsyncLifetime.InitializeAsync()
+        {
+           await this.functionsHost.StartAsync();
+        }
 
-        Task IAsyncLifetime.DisposeAsync() => this.functionsHost.StopAsync();
+        async Task IAsyncLifetime.DisposeAsync() 
+        {
+            try
+            {
+                await this.functionsHost.StopAsync();
+            }
+            catch(OperationCanceledException)
+            {
+
+            }
+        }
 
         protected void AddFunctions(Type functionType) => this.typeLocator.AddFunctionType(functionType);