Added null checks on callbacks themselves that way each callback doesnt require others to not be null in order to run. Also added test coverage for the case of the signal callback bug

Author: Morgan Moon

PubNubUnity/Assets/PubNub/Editor/SignalTest.cs

@@ -22,6 +22,23 @@ public void TestSignalRequestQueryParam ()
             TestSignalCommon (true, true);
         }
 
+        [Test]
+        public void TestAddListenerSignalCallback ()
+        {
+            PNConfiguration pnConfiguration = new PNConfiguration ();
+            PubNubUnity pnUnity = new PubNubUnity(pnConfiguration, null, null);
+            bool receivedCallback = false;
+            Action<PNSignalEventResult> callback = (pnser) => receivedCallback = true;
+            pnUnity.AddListener(null, null, null, callback, null, null, null, null);
+
+            pnUnity.RaiseEvent(new SubscribeEventEventArgs()
+            {
+                SignalEventResult = new PNSignalEventResult(null, null, null, 0, 0, null, null)
+            });
+
+            Assert.IsTrue(receivedCallback);
+        }
+
         public void TestSignalCommon(bool ssl, bool sendQueryParams){
             string channel = EditorCommon.GetRandomChannelName();
             string message = "Test signal";

PubNubUnity/Assets/PubNub/PubNubUnity/PubNubUnity.cs

@@ -70,28 +70,28 @@ public void AddListener(Action<PNStatus> statusCallback, Action<PNMessageResult>
                 #endif
 
                 if(mea!=null){
-                    if(mea.Status != null){
+                    if(mea.Status != null && statusCallback != null){
                         statusCallback(mea.Status);
                     }
-                    if(mea.MessageResult != null){
+                    if(mea.MessageResult != null && messageCallback != null){
                         messageCallback(mea.MessageResult);
                     }
-                    if(mea.PresenceEventResult != null){
+                    if(mea.PresenceEventResult != null && presenceCallback != null){
                         presenceCallback(mea.PresenceEventResult);
                     }
-                    if(mea.SignalEventResult != null){
+                    if(mea.SignalEventResult != null && signalCallback != null){
                         signalCallback(mea.SignalEventResult);
                     }
-                    if(mea.UserEventResult != null){
+                    if(mea.UserEventResult != null && userCallback != null){
                         userCallback(mea.UserEventResult);
                     }
-                    if(mea.SpaceEventResult != null){
+                    if(mea.SpaceEventResult != null && spaceCallback != null){
                         spaceCallback(mea.SpaceEventResult);
                     }
-                    if(mea.MembershipEventResult != null){
+                    if(mea.MembershipEventResult != null && membershipCallback != null){
                         membershipCallback(mea.MembershipEventResult);
                     }
-                    if(mea.MessageActionsEventResult != null){
+                    if(mea.MessageActionsEventResult != null && messageActionsCallback != null){
                         messageActionsCallback(mea.MessageActionsEventResult);
                     }