diff --git a/roles/upload-logs-gcs/library/test-fixtures/auth.json b/roles/upload-logs-gcs/library/test-fixtures/auth.json
new file mode 100644
index 000000000..8df1606b6
--- /dev/null
+++ b/roles/upload-logs-gcs/library/test-fixtures/auth.json
@@ -0,0 +1 @@
+{"access_token": "something", "expires_in": 3599, "token_type": "Bearer"}
diff --git a/roles/upload-logs-gcs/library/test_zuul_google_storage_upload.py b/roles/upload-logs-gcs/library/test_zuul_google_storage_upload.py
index ed5c55627..16a7831d8 100644
--- a/roles/upload-logs-gcs/library/test_zuul_google_storage_upload.py
+++ b/roles/upload-logs-gcs/library/test_zuul_google_storage_upload.py
@@ -26,6 +26,7 @@ import fixtures
 
 from bs4 import BeautifulSoup
 from .zuul_google_storage_upload import FileList, Indexer, FileDetail
+from .zuul_google_storage_upload import Credentials
 
 
 FIXTURE_DIR = os.path.join(os.path.dirname(__file__),
@@ -404,3 +405,13 @@ class TestFileDetail(testtools.TestCase):
 
         self.assertEqual(time.gmtime(0), file_detail.last_modified)
         self.assertEqual(0, file_detail.size)
+
+
+class TestCredential(testtools.TestCase):
+
+    def test_credential(self):
+        path = os.path.join(FIXTURE_DIR, 'auth.json')
+        headers = {}
+        c = Credentials(path)
+        c.before_request(None, None, None, headers)
+        self.assertEqual("Bearer something", headers['authorization'])
diff --git a/roles/upload-logs-gcs/library/zuul_google_storage_upload.py b/roles/upload-logs-gcs/library/zuul_google_storage_upload.py
index b0c5eef7d..88ccd2eea 100755
--- a/roles/upload-logs-gcs/library/zuul_google_storage_upload.py
+++ b/roles/upload-logs-gcs/library/zuul_google_storage_upload.py
@@ -260,7 +260,7 @@ def sizeof_fmt(num, suffix='B'):
 
 class Credentials(gce_cred.Credentials):
     def __init__(self, path):
-        super().__init__()
+        super(Credentials, self).__init__()
         self._path = path
         self.refresh(None)