Reformat the source code using black

Change-Id: I54e7f6b9a60e4caa42158bf6259c671bc800e4a8
diff --git a/tests/tests.py b/tests/tests.py
index 69507e1..a0458e7 100644
--- a/tests/tests.py
+++ b/tests/tests.py
@@ -22,9 +22,10 @@
 class CinderStorPoolTest(CinderBackendTest):
     """Encapsulate StorPool tests."""
 
-    backend_name = 'StorPool'
+    backend_name = "StorPool"
 
     expected_config_content = {
-        'StorPool': {
-            'volume-backend-name': ['StorPool'],
-        }}
+        "StorPool": {
+            "volume-backend-name": ["StorPool"],
+        }
+    }