diff --git a/src/wuttjamaican/testing.py b/src/wuttjamaican/testing.py
index 2461674..2744e63 100644
--- a/src/wuttjamaican/testing.py
+++ b/src/wuttjamaican/testing.py
@@ -105,7 +105,9 @@ class FileTestCase(TestCase):
             f.write(content)
         return path
 
-    def mkdir(self, dirname):  # pylint: disable=unused-argument,empty-docstring
+    def mkdir(  # pragma: no cover; pylint: disable=unused-argument,empty-docstring
+        self, dirname
+    ):
         """ """
         warnings.warn(
             "FileTestCase.mkdir() is deprecated; "