diff --git a/tests/test_filereporter.py b/tests/test_filereporter.py
index 5064081dc..1d072daea 100644
--- a/tests/test_filereporter.py
+++ b/tests/test_filereporter.py
@@ -103,7 +103,7 @@ def test_zipfile(self) -> None:
         assert z1.source() == ""
         assert "# My zip file!" in z1z1.source().splitlines()
 
-    def test_python_extensions(self):
+    def test_python_extensions(self) -> None:
         f1 = PythonFileReporter("afile.py")
         f2 = PythonFileReporter("Makefile")
         f3 = PythonFileReporter("template.jinja")