fixed tests

Tests/MQTTnet.Core.Tests/MqttServerTests.cs

@@ -209,12 +209,9 @@ namespace MQTTnet.Core.Tests
                 await s.StartAsync(new MqttServerOptions());
 
                 var c1 = await serverAdapter.ConnectTestClient(s, "c1");
-                await c1.PublishAsync(new MqttApplicationMessageBuilder().WithTopic("retained").WithPayload(new byte[3]).WithRetainFlag().Build());
+                await c1.PublishAndWaitForAsync(s, new MqttApplicationMessageBuilder().WithTopic("retained").WithPayload(new byte[3]).WithRetainFlag().Build());
                 await c1.DisconnectAsync();
 
-                await Task.Delay(TimeSpan.FromSeconds(2));
-                // TODO: Find another way to wait for the retained components.
-
                 var c2 = await serverAdapter.ConnectTestClient(s, "c2");
                 c2.ApplicationMessageReceived += (_, __) => receivedMessagesCount++;
                 await c2.SubscribeAsync(new TopicFilterBuilder().WithTopic("retained").Build());
@@ -244,7 +241,7 @@ namespace MQTTnet.Core.Tests
                 await c1.PublishAsync(new MqttApplicationMessageBuilder().WithTopic("retained").WithPayload(new byte[3]).WithRetainFlag().Build());
                 await c1.PublishAsync(new MqttApplicationMessageBuilder().WithTopic("retained").WithPayload(new byte[0]).WithRetainFlag().Build());
                 await c1.DisconnectAsync();
-
+                
                 var c2 = await serverAdapter.ConnectTestClient(s, "c2");
                 c2.ApplicationMessageReceived += (_, __) => receivedMessagesCount++;
                 await c2.SubscribeAsync(new TopicFilter("retained", MqttQualityOfServiceLevel.AtMostOnce));
@@ -274,7 +271,8 @@ namespace MQTTnet.Core.Tests
                 await s.StartAsync(options);
 
                 var c1 = await serverAdapter.ConnectTestClient(s, "c1");
-                await c1.PublishAsync(new MqttApplicationMessageBuilder().WithTopic("retained").WithPayload(new byte[3]).WithRetainFlag().Build());
+
+                await c1.PublishAndWaitForAsync(s, new MqttApplicationMessageBuilder().WithTopic("retained").WithPayload(new byte[3]).WithRetainFlag().Build());
                 await c1.DisconnectAsync();
             }
             finally
@@ -282,8 +280,7 @@ namespace MQTTnet.Core.Tests
                 await s.StopAsync();
             }
 
-            await Task.Delay(TimeSpan.FromSeconds(2));
-            // TODO: Find another way to wait for the retained components.
+            Assert.AreEqual(1, storage.Messages.Count);
 
             s = new MqttFactory().CreateMqttServer(new[] { serverAdapter }, new MqttNetLogger());
 
@@ -385,17 +382,17 @@ namespace MQTTnet.Core.Tests
 
         private class TestStorage : IMqttServerStorage
         {
-            private IList<MqttApplicationMessage> _messages = new List<MqttApplicationMessage>();
+            public IList<MqttApplicationMessage> Messages = new List<MqttApplicationMessage>();
 
             public Task SaveRetainedMessagesAsync(IList<MqttApplicationMessage> messages)
             {
-                _messages = messages;
+                Messages = messages;
                 return Task.CompletedTask;
             }
 
             public Task<IList<MqttApplicationMessage>> LoadRetainedMessagesAsync()
             {
-                return Task.FromResult(_messages);
+                return Task.FromResult(Messages);
             }
         }
 

Tests/MQTTnet.Core.Tests/TestServerExtensions.cs

@@ -0,0 +1,38 @@
+using MQTTnet.Client;
+using MQTTnet.Server;
+using System;
+using System.Threading.Tasks;
+
+namespace MQTTnet.Core.Tests
+{
+    public static class TestServerExtensions
+    {
+        /// <summary>
+        /// publishes a message with a client and waits in the server until a message with the same topic is received
+        /// </summary>
+        /// <returns></returns>
+        public static async Task PublishAndWaitForAsync(this IMqttClient client, IMqttServer server, MqttApplicationMessage message) 
+        {
+            var tcs = new TaskCompletionSource<object>();
+
+            EventHandler<MqttApplicationMessageReceivedEventArgs> handler = (sender, args) =>
+            {
+                if (args.ApplicationMessage.Topic == message.Topic)
+                {
+                    tcs.SetResult(true);
+                }
+            };
+            server.ApplicationMessageReceived += handler;
+            
+            try
+            {
+                await client.PublishAsync(message);
+                await tcs.Task;
+            }
+            finally
+            {
+                server.ApplicationMessageReceived -= handler;
+            }
+        }
+    }
+}