diff --git a/tests/utils/test_fs.py b/tests/utils/test_fs.py
index c856a234..39708c3d 100644
--- a/tests/utils/test_fs.py
+++ b/tests/utils/test_fs.py
@@ -78,4 +78,4 @@ def test_backup_dir_trailing_slash(tmp):
 
 def test_backup_timestamp(tmp):
     bkfile = fs.backup(tmp.file, timestamp=True)
-    assert re.match('(.*).bak-[\d]+-[\d]+-[\d]+(.*)', bkfile)  # noqa: W605
+    assert re.match(r'(.*).bak-[\d]+-[\d]+-[\d]+(.*)', bkfile)  # noqa: W605