Added test for double subscription message to the same topic

parser/src/main/java/org/dna/mqtt/moquette/messaging/spi/impl/SimpleMessaging.java

@@ -18,7 +18,11 @@ public class SimpleMessaging implements IMessaging {
     }
 
     public void subscribe(String clientId, String topic, QOSType qos) {
-        subscriptions.add(new Subscription(clientId, topic, qos));
+        Subscription newSubscription = new Subscription(clientId, topic, qos);
+        if (subscriptions.contains(newSubscription)) {
+            return;
+        }
+        subscriptions.add(newSubscription);
     }
     
     protected List<Subscription> getSubscriptions() {

parser/src/test/java/org/dna/mqtt/moquette/messaging/spi/impl/SimpleMessagingTest.java

@@ -1,10 +1,7 @@
 package org.dna.mqtt.moquette.messaging.spi.impl;
 
+import java.util.List;
 import org.dna.mqtt.moquette.proto.messages.AbstractMessage.QOSType;
-import org.junit.After;
-import org.junit.AfterClass;
-import org.junit.Before;
-import org.junit.BeforeClass;
 import org.junit.Test;
 import static org.junit.Assert.*;
 
@@ -43,6 +40,32 @@ public class SimpleMessagingTest {
         messaging.subscribe(clientID, topic, QOSType.MOST_ONE);
         
         //Verify
-        assertTrue(messaging.getSubscriptions().contains(new Subscription(clientID, topic, QOSType.MOST_ONE)));
+        Subscription expectedSubscription = new Subscription(clientID, topic, QOSType.MOST_ONE);
+        assertTrue(messaging.getSubscriptions().contains(expectedSubscription));
+    }
+    
+    @Test
+    public void testDoubleSubscribe() {
+        String clientID = "FAKE_123";
+        String topic = "/news";
+        SimpleMessaging messaging = new SimpleMessaging();
+        messaging.subscribe(clientID, topic, QOSType.MOST_ONE);
+        
+        //Exercise
+        messaging.subscribe(clientID, topic, QOSType.MOST_ONE);
+        
+        //Verify
+        Subscription subscription = new Subscription(clientID, topic, QOSType.MOST_ONE);
+        assertEquals(1, countMatchingSubscriptions(messaging.getSubscriptions(), subscription));
+    }
+    
+    private int countMatchingSubscriptions(List<Subscription> l, Subscription matchingSub) {
+        int count = 0;
+        for (Subscription s : l) {
+            if (s.equals(matchingSub)) {
+                count++;
+            }
+        }
+        return count;
     }
 }

parser/src/test/java/org/dna/mqtt/moquette/server/MQTTHandlerTest.java

@@ -109,5 +109,11 @@ public class MQTTHandlerTest {
         ArgumentCaptor<AbstractMessage.QOSType> argument = ArgumentCaptor.forClass(AbstractMessage.QOSType.class);
         verify(mockedMessaging).subscribe(eq("fakeID"), eq(topicName), argument.capture());
         assertEquals(AbstractMessage.QOSType.EXACTLY_ONCE, argument.getValue());
+        //TODO verify the message ACK and corresponding QoS!!
     }
+    
+//    @Test
+//    public void testHandleSubscribeMultipleTopics() {
+//        fail("TOBE implemented");
+//    }
 }