--- a/testing/raptor/raptor/output.py
+++ b/testing/raptor/raptor/output.py
@@ -731,17 +731,17 @@ class Output(object):
                         screenshot['screenshot'],
                         screenshot['test_name'],
                         screenshot['page_cycle']))
 
         self.summarized_screenshots.append("""</table></body> </html>""")
 
     def output(self, test_names):
         """output to file and perfherder data json """
-        if os.environ['MOZ_UPLOAD_DIR']:
+        if os.getenv('MOZ_UPLOAD_DIR'):
             # i.e. testing/mozharness/build/raptor.json locally; in production it will
             # be at /tasks/task_*/build/ (where it will be picked up by mozharness later
             # and made into a tc artifact accessible in treeherder as perfherder-data.json)
             results_path = os.path.join(os.path.dirname(os.environ['MOZ_UPLOAD_DIR']),
                                         'raptor.json')
             screenshot_path = os.path.join(os.path.dirname(os.environ['MOZ_UPLOAD_DIR']),
                                            'screenshots.html')
         else: