diff --git a/beets/test/_common.py b/beets/test/_common.py
index 1d2788c728..22abe3349d 100644
--- a/beets/test/_common.py
+++ b/beets/test/_common.py
@@ -144,7 +144,9 @@ class Assertions:
     """A mixin with additional unit test assertions."""
 
     def assertExists(self, path):  # noqa
-        assert os.path.exists(syspath(path)), f"file does not exist: {repr(path)}"
+        assert os.path.exists(
+            syspath(path)
+        ), f"file does not exist: {repr(path)}"
 
     def assertNotExists(self, path):  # noqa
         assert not os.path.exists(syspath(path)), f"file exists: {repr(path)}"