BQ-DTS: test for actual API output (GoogleCloudPlatform#597)

Author: tswast

bigquerydatatransfer/quickstart.php

@@ -42,4 +42,3 @@
     $bqdtsClient->close();
 }
 # [END bigquerydatatransfer_quickstart]
-return true;

bigquerydatatransfer/test/quickstartTest.php

@@ -34,10 +34,12 @@ public function testQuickstart()
         );
         file_put_contents($file, $contents);
 
-        // Invoke quickstart.php
-        $this->result = include $file;
+        // Invoke quickstart.php and capture output
+        ob_start();
+        include $file;
+        $result = ob_get_clean();
 
         // Make sure it looks correct
-        $this->assertTrue($this->result);
+        $this->assertContains('ID: youtube_channel', $result);
     }
 }