diff --git a/tests/testing.py b/tests/testing.py
index d3cd4217..e9f77310 100644
--- a/tests/testing.py
+++ b/tests/testing.py
@@ -82,7 +82,7 @@ def setup_class(cls):
             [join(cls._source_dir, file) for file in cls.files],
             cls._source_dir,
             "tsconfig.json",
-            cls._source_dir
+            cls._source_dir,
         )
         Converter(cls._source_dir).populate_index(cls.json)