diff --git a/tests/test_black.py b/tests/test_black.py
index 31bc34d4b89..8fa352e3d22 100644
--- a/tests/test_black.py
+++ b/tests/test_black.py
@@ -114,7 +114,7 @@ class BlackRunner(CliRunner):
     """Make sure STDOUT and STDERR are kept separate when testing Black via its CLI."""
 
     def __init__(self) -> None:
-        super().__init__(mix_stderr=False)
+        super().__init__()
 
 
 def invokeBlack(