fix: Return error if subscription name already exists.

src/index.js

@@ -230,7 +230,7 @@ class PubSub {
         gaxOpts: options.gaxOpts,
       },
       function(err, resp) {
-        if (err && err.code !== 6) {
+        if (err) {
           callback(err, null, resp);
           return;
         }

system-test/pubsub.js

@@ -300,6 +300,26 @@ describe('pubsub', function() {
       );
     });
 
+    it('should return error if creating an existing subscription', function(done) {
+      // Use a new topic name...
+      const topic = pubsub.topic(generateTopicName());
+
+      // ...but with the same subscription name that we already created...
+      const subscription = topic.subscription(SUB_NAMES[0]);
+
+      subscription.create(function(err) {
+        if (!err) {
+          assert.fail('Should not have created subscription successfully.');
+          return;
+        }
+
+        // ...and it should fail, because the subscription name is unique to the
+        // project, and not the topic.
+        assert.strictEqual(err.code, 6);
+        done();
+      });
+    });
+
     it('should list all subscriptions registered to the topic', function(done) {
       topic.getSubscriptions(function(err, subs) {
         assert.ifError(err);
@@ -442,10 +462,6 @@ describe('pubsub', function() {
         });
     });
 
-    it('should re-use an existing subscription', function(done) {
-      pubsub.createSubscription(topic, SUB_NAMES[0], done);
-    });
-
     it('should error when using a non-existent subscription', function(done) {
       const subscription = topic.subscription(generateSubName(), {
         maxConnections: 1,

test/index.js

@@ -481,24 +481,6 @@ describe('PubSub', function() {
         };
       });
 
-      it('should re-use existing subscription', function(done) {
-        const apiResponse = {code: 6};
-
-        pubsub.subscription = function() {
-          return SUBSCRIPTION;
-        };
-
-        pubsub.request = function(config, callback) {
-          callback({code: 6}, apiResponse);
-        };
-
-        pubsub.createSubscription(TOPIC_NAME, SUB_NAME, function(err, sub) {
-          assert.ifError(err);
-          assert.strictEqual(sub, SUBSCRIPTION);
-          done();
-        });
-      });
-
       it('should return error & API response to the callback', function(done) {
         pubsub.request = function(config, callback) {
           callback(error, apiResponse);