pubsub: fixed subscription pulling bug

Each time a message event was listened for, startPulling_ would be
called increasing the total number of requests being made. This change
added a check to prevent startPulling_ from being called when it didn't
need to be

lib/pubsub/subscription.js

@@ -134,7 +134,7 @@ function Subscription(pubsub, options) {
   this.makeReq_ = pubsub.makeReq_.bind(pubsub);
 
   this.autoAck = util.is(options.autoAck, 'boolean') ? options.autoAck : false;
-  this.closed = false;
+  this.closed = true;
   this.interval = util.is(options.interval, 'number') ? options.interval : 10;
   this.inProgressAckIds = {};
   this.maxInProgress =
@@ -210,16 +210,16 @@ Subscription.prototype.listenForEvents_ = function() {
 
   this.on('newListener', function(event) {
     if (event === 'message') {
-      this.messageListeners++;
+      self.messageListeners++;
       if (self.closed) {
         self.closed = false;
+        self.startPulling_();
       }
-      self.startPulling_();
     }
   });
 
   this.on('removeListener', function(event) {
-    if (event === 'message' && --this.messageListeners === 0) {
+    if (event === 'message' && --self.messageListeners === 0) {
       self.closed = true;
     }
   });

test/pubsub/subscription.js

@@ -75,8 +75,8 @@ describe('Subscription', function() {
       assert.strictEqual(sub.maxInProgress, 3);
     });
 
-    it('should not be closed', function() {
-      assert.strictEqual(subscription.closed, false);
+    it('should be closed', function() {
+      assert.strictEqual(subscription.closed, true);
     });
 
     it('should default autoAck to false if not specified', function() {
@@ -145,6 +145,19 @@ describe('Subscription', function() {
       assert.strictEqual(subscription.messageListeners, 0);
     });
 
+    it('should only run a single pulling loop', function() {
+      var startPullingCallCount = 0;
+
+      subscription.startPulling_ = function() {
+        startPullingCallCount++;
+      };
+
+      subscription.on('message', util.noop);
+      subscription.on('message', util.noop);
+
+      assert.strictEqual(startPullingCallCount, 1);
+    });
+
     it('should close when no more message listeners are bound', function() {
       subscription.startPulling_ = util.noop;
       subscription.on('message', util.noop);
@@ -478,6 +491,8 @@ describe('Subscription', function() {
         assert.strictEqual(options.returnImmediately, false);
         done();
       };
+
+      subscription.closed = false;
       subscription.startPulling_();
     });
 
@@ -486,6 +501,8 @@ describe('Subscription', function() {
         assert.strictEqual(options.maxResults, undefined);
         done();
       };
+
+      subscription.closed = false;
       subscription.startPulling_();
     });
 
@@ -494,6 +511,8 @@ describe('Subscription', function() {
         assert.strictEqual(options.maxResults, 1);
         done();
       };
+
+      subscription.closed = false;
       subscription.maxInProgress = 4;
       subscription.inProgressAckIds = { id1: true, id2: true, id3: true };
       subscription.startPulling_();
@@ -507,6 +526,8 @@ describe('Subscription', function() {
           callback(error);
         });
       };
+
+      subscription.closed = false;
       subscription
         .once('error', function(err) {
           assert.equal(err, error);
@@ -524,6 +545,8 @@ describe('Subscription', function() {
           callback(error, null, resp);
         });
       };
+
+      subscription.closed = false;
       subscription
         .once('error', function(err, apiResponse) {
           assert.equal(err, error);
@@ -537,6 +560,7 @@ describe('Subscription', function() {
       subscription.pull = function(options, callback) {
         callback(null, [{ hi: 'there' }]);
       };
+
       subscription
         .once('message', function(msg) {
           assert.deepEqual(msg, { hi: 'there' });
@@ -576,6 +600,8 @@ describe('Subscription', function() {
         // above.
         fn();
       };
+
+      subscription.closed = false;
       subscription.interval = INTERVAL;
       subscription.startPulling_();
     });