Added tests for channel/presence subscribe without implicit attach

Author: sacOO7

lib/src/main/java/io/ably/lib/realtime/Presence.java

@@ -309,7 +309,9 @@ public void unsubscribe() {
      */
     private void implicitAttachOnSubscribe(CompletionListener completionListener) throws AblyException {
         if (!channel.attachOnSubscribeEnabled()) {
-            completionListener.onSuccess();
+            if (completionListener != null) {
+                completionListener.onSuccess();
+            }
             return;
         }
         if (channel.state == ChannelState.failed) {

lib/src/test/java/io/ably/lib/test/realtime/RealtimeChannelTest.java

@@ -393,6 +393,68 @@ public void onMessage(Message message) {
         }
     }
 
+    /**
+     * <p>
+     * Validates a client can subscribe to messages without implicit channel attach
+     * Refer Spec TB4, RTL7g, RTL7gh
+     * </p>
+     * @throws AblyException
+     */
+    @Test
+    public void subscribe_without_implicit_attach() {
+        String channelName = "subscribe_" + testParams.name;
+        AblyRealtime ably = null;
+        try {
+            ClientOptions opts = createOptions(testVars.keys[0].keyStr);
+            ably = new AblyRealtime(opts);
+
+            /* create a channel and set attachOnSubscribe to false */
+            final Channel channel = ably.channels.get(channelName);
+            ChannelOptions chOpts = new ChannelOptions();
+            chOpts.attachOnSubscribe = false;
+            channel.setOptions(chOpts);
+
+            List<Object> receivedMsg = new ArrayList<>();
+
+            /* Check for all subscriptions without ATTACHING state */
+            channel.subscribe(message -> receivedMsg.add(true));
+            assertEquals(channel.state, ChannelState.initialized);
+
+            channel.subscribe("test_event", message -> receivedMsg.add(true));
+            assertEquals(channel.state, ChannelState.initialized);
+
+            channel.subscribe(new String[]{"test_event1", "test_event2"}, message -> receivedMsg.add(true));
+            assertEquals(channel.state, ChannelState.initialized);
+
+            channel.attach();
+            (new ChannelWaiter(channel)).waitFor(ChannelState.attached);
+
+            channel.publish("test_event", "hi there");
+            Exception conditionError = new Helpers.ConditionalWaiter().
+                wait(() -> receivedMsg.size() == 2, 5000);
+            assertNull(conditionError);
+
+            receivedMsg.clear();
+            channel.publish("test_event1", "hi there");
+            conditionError = new Helpers.ConditionalWaiter().
+                wait(() -> receivedMsg.size() == 2, 5000);
+            assertNull(conditionError);
+
+            receivedMsg.clear();
+            channel.publish("test_event2", "hi there");
+            conditionError = new Helpers.ConditionalWaiter().
+                wait(() -> receivedMsg.size() == 2, 5000);
+            assertNull(conditionError);
+
+        } catch (AblyException e) {
+            e.printStackTrace();
+            fail("init0: Unexpected exception instantiating library");
+        } finally {
+            if(ably != null)
+                ably.close();
+        }
+    }
+
     /**
      * <p>
      * Verifies that unsubscribe call with no argument removes all listeners,

lib/src/test/java/io/ably/lib/test/realtime/RealtimePresenceTest.java

@@ -1624,6 +1624,66 @@ public void onPresenceMessage(PresenceMessage message) {
         }
     }
 
+    /**
+     * <p>
+     * Validates a client can subscribe to presence without implicit channel attach
+     * Refer Spec TB4, RTP6d, RTP6e
+     * </p>
+     * @throws AblyException
+     */
+    @Test
+    public void presence_subscribe_without_implicit_attach() {
+        String ablyChannel = "subscribe_" + testParams.name;
+        AblyRealtime ably = null;
+        try {
+            ClientOptions option1 = createOptions(testVars.keys[0].keyStr);
+            option1.clientId = "client1";
+            ably = new AblyRealtime(option1);
+
+            /* create a channel and set attachOnSubscribe to false */
+            final Channel channel = ably.channels.get(ablyChannel);
+            ChannelOptions chOpts = new ChannelOptions();
+            chOpts.attachOnSubscribe = false;
+            channel.setOptions(chOpts);
+
+            List<Object> receivedPresenceMsg = new ArrayList<>();
+            CompletionWaiter completionWaiter = new CompletionWaiter();
+
+            /* Check for all subscriptions without ATTACHING state */
+            channel.presence.subscribe(m -> receivedPresenceMsg.add(true), completionWaiter);
+            assertEquals(completionWaiter.successCount, 1);
+            assertEquals(channel.state, ChannelState.initialized);
+
+            channel.presence.subscribe(Action.enter, m -> receivedPresenceMsg.add(true), completionWaiter);
+            assertEquals(completionWaiter.successCount, 2);
+            assertEquals(channel.state, ChannelState.initialized);
+
+            channel.presence.subscribe(EnumSet.of(Action.enter, Action.leave),m -> receivedPresenceMsg.add(true));
+            assertEquals(channel.state, ChannelState.initialized);
+
+            channel.attach();
+            (new ChannelWaiter(channel)).waitFor(ChannelState.attached);
+
+            channel.presence.enter("enter client1", null);
+            Exception conditionError = new Helpers.ConditionalWaiter().
+                wait(() -> receivedPresenceMsg.size() == 3, 5000);
+            assertNull(conditionError);
+
+            receivedPresenceMsg.clear();
+            channel.presence.leave(null);
+            conditionError = new Helpers.ConditionalWaiter().
+                wait(() -> receivedPresenceMsg.size() == 2, 5000);
+            assertNull(conditionError);
+
+        } catch (AblyException e) {
+            e.printStackTrace();
+            fail("init0: Unexpected exception instantiating library");
+        } finally {
+            if(ably != null)
+                ably.close();
+        }
+    }
+
     /**
      * <p>
      * Validates a client sending multiple presence updates when the channel is in the attaching