Develop (#1)

* Add env var to supress missing credentials warning

* Do not delete topic when last message pop

Author: kainxspirits

src/PubSubQueue.php

@@ -133,7 +133,6 @@ public function pop($queue = null)
             );
         } else {
             $subscription->delete();
-            $topic->delete();
         }
     }
 

tests/Unit/Connectors/PubSubConnectorTests.php

@@ -12,6 +12,7 @@ class PubSubConnectorTests extends TestCase
 {
     public function testImplementsConnectorInterface()
     {
+        putenv('SUPPRESS_GCLOUD_CREDS_WARNING=true');
         $reflection = new ReflectionClass(PubSubConnector::class);
         $this->assertTrue($reflection->implementsInterface(ConnectorInterface::class));
     }

tests/Unit/PubSubQueueTests.php

@@ -135,9 +135,6 @@ public function testPopWhenNoJobAvailable()
         $this->topic->method('exists')
             ->willReturn(true);
 
-        $this->topic->expects($this->once())
-            ->method('delete');
-
         $this->queue->method('getTopic')
             ->willReturn($this->topic);