diff --git a/tests/test_black.py b/tests/test_black.py
index 078e8d8..b3f1f82 100644
--- a/tests/test_black.py
+++ b/tests/test_black.py
@@ -289,7 +289,7 @@ def test_expression_diff(self) -> None:
             msg = (
                 f"Expected diff isn't equal to the actual. If you made changes "
                 f"to expression.py and this is an anticipated difference, "
-                f"overwrite tests/expression.diff with {dump}"
+                f"overwrite tests/data/expression.diff with {dump}"
             )
             self.assertEqual(expected, actual, msg)