Receive should not throw timeout exception (#130)

* Update readme.md (#110)

Fixed broken links.

* ReceiveAsync call should return NULL instead of throwing System.TimeoutException

src/Microsoft.Azure.EventHubs/Amqp/AmqpPartitionReceiver.cs

@@ -110,6 +110,13 @@ namespace Microsoft.Azure.EventHubs.Amqp
                     }
                     else
                     {
+                        // Handle System.TimeoutException explicitly.
+                        // We don't really want to to throw TimeoutException on this call.
+                        if (ex is TimeoutException)
+                        {
+                            break;
+                        }
+
                         throw;
                     }
                 }

test/Microsoft.Azure.EventHubs.UnitTests/EventHubClientTests.cs

@@ -748,6 +748,50 @@ namespace Microsoft.Azure.EventHubs.UnitTests
             }
         }
 
+        /// <summary>
+        /// Small receive timeout should not throw System.TimeoutException. 
+        /// TimeoutException should be returned as NULL to the awaiting client.
+        /// </summary>
+        /// <returns></returns>
+        [Fact]
+        async Task SmallReceiveTimeout()
+        {
+            var maxClients = 5;
+
+            // Issue receives with 1 second so that some of the Receive calls will timeout while creating AMQP link.
+            // Even those Receive calls should return NULL instead of bubbling the exception up.
+            var receiveTimeoutInSeconds = 1;
+
+            var tasks = Enumerable.Range(0, maxClients)
+                .Select(async i =>
+                {
+                    PartitionReceiver receiver = null;
+
+                    try
+                    {
+                        Log($"Testing with {receiveTimeoutInSeconds} seconds on client {i}.");
+
+                        // Start receiving from a future time so that Receive call won't be able to fetch any events.
+                        var ehClient = EventHubClient.CreateFromConnectionString(this.EventHubsConnectionString);
+                        receiver = ehClient.CreateReceiver(PartitionReceiver.DefaultConsumerGroupName, "0", DateTime.UtcNow.AddMinutes(1));
+                        var ed = await receiver.ReceiveAsync(1, TimeSpan.FromSeconds(receiveTimeoutInSeconds));
+                        if (ed == null)
+                        {
+                            Log($"Received NULL from client {i}");
+                        }
+                    }
+                    finally
+                    {
+                        if (receiver != null)
+                        {
+                            await receiver.CloseAsync();
+                        }
+                    }
+                });
+
+            await Task.WhenAll(tasks);
+        }
+
         [Fact]
         async Task PartitionKeyValidation()
         {