diff --git a/tests/test_pylast.py b/tests/test_pylast.py
index 789afad..c734d32 100755
--- a/tests/test_pylast.py
+++ b/tests/test_pylast.py
@@ -34,11 +34,11 @@ def load_secrets():  # pragma: no cover
 
 
 class PyLastTestCase:
-    def assert_startswith(self, str, prefix, start=None, end=None):
-        assert str.startswith(prefix, start, end)
+    def assert_startswith(self, s, prefix, start=None, end=None):
+        assert s.startswith(prefix, start, end)
 
-    def assert_endswith(self, str, suffix, start=None, end=None):
-        assert str.endswith(suffix, start, end)
+    def assert_endswith(self, s, suffix, start=None, end=None):
+        assert s.endswith(suffix, start, end)
 
 
 def _no_xfail_rerun_filter(err, name, test, plugin):