fix issue that message properties are not sent out when using MQTT

device/iot-device-client/src/main/java/com/microsoft/azure/sdk/iot/device/transport/mqtt/MqttMessaging.java

@@ -4,6 +4,7 @@
 package com.microsoft.azure.sdk.iot.device.transport.mqtt;
 
 import com.microsoft.azure.sdk.iot.device.Message;
+import com.microsoft.azure.sdk.iot.device.MessageProperty;
 
 import java.io.IOException;
 import java.util.Map;
@@ -167,10 +168,34 @@ public void send(Message message) throws IOException
             throw new IOException("Message cannot be null");
         }
 
+        MessageProperty[] messageProperties = message.getProperties();
+        String messagePublishTopic;
+        if(messageProperties.length > 0)
+        {
+            StringBuilder stringBuilder = new StringBuilder();
+            stringBuilder.append(this.publishTopic);
+            boolean needAmpersand = false;
+            for(MessageProperty property : message.getProperties())
+            {
+                if(needAmpersand)
+                {
+                    stringBuilder.append('&');
+                }
+                stringBuilder.append(property.getName());
+                stringBuilder.append('=');
+                stringBuilder.append(property.getValue());
+                needAmpersand = true;
+            }
+            messagePublishTopic = stringBuilder.toString();
+        }
+        else
+        {
+            messagePublishTopic = this.publishTopic;
+        }
         /*
         **Codes_SRS_MqttMessaging_25_024: [**send method shall publish a message to the IOT Hub on the publish topic by calling method publish().**]**
          */
-        this.publish(this.publishTopic, message.getBytes());
+        this.publish(messagePublishTopic, message.getBytes());
 
     }
 

device/iot-device-client/src/test/java/tests/unit/com/microsoft/azure/sdk/iot/device/transport/mqtt/MqttMessagingTest.java

@@ -6,6 +6,7 @@
 
 import com.microsoft.azure.sdk.iot.device.Message;
 
+import com.microsoft.azure.sdk.iot.device.MessageProperty;
 import mockit.*;
 
 import org.junit.Test;
@@ -435,7 +436,6 @@ public void sendShallMessageToLowerLayer(@Mocked final Mqtt mockMqtt) throws IOE
             }
         };
 
-
     }
 
     @Test (expected =  IOException.class)
@@ -492,5 +492,45 @@ public void sendShallThrowIOExceptionIfMessageIsNull(@Mocked final Mqtt mockMqtt
 
     }
 
+    /*
+     **Tests_SRS_MqttMessaging_25_026: [**send method shall publish a message to the IOT Hub on the publish topic with message property bag by calling method publish().**]**
+     */
+    @Test
+    public void sendShallMessageWithPropertiesToLowerLayer(@Mocked final Mqtt mockMqtt) throws IOException
+    {
+        final byte[] messageBody = {0x61, 0x62, 0x63};
+        final String propertyName = "key";
+        final String propertyValue = "value";
+        final MessageProperty[] messageProperties = new MessageProperty[]
+                {
+                        new MessageProperty(propertyName, propertyValue)
+                };
+        new NonStrictExpectations()
+        {
+            {
+                mockMessage.getBytes();
+                result = messageBody;
+                mockMessage.getProperties();
+                result = messageProperties;
+                mockMqtt.publish(anyString, messageBody);
+            }
+        };
+
+        MqttMessaging testMqttMessaging = new MqttMessaging(serverUri, clientId, userName, password);
+        testMqttMessaging.send(mockMessage);
+        final String publishTopicWithProperties = String.format(
+                "devices/%s/messages/events/%s=%s", clientId, propertyName, propertyValue);
+
+        new Verifications()
+        {
+            {
+                mockMessage.getBytes();
+                times = 2;
+                mockMessage.getProperties();
+                mockMqtt.publish(publishTopicWithProperties, messageBody);
+                times = 1;
+            }
+        };
+    }
 
 }