diff --git a/src/_pytest/pytester.py b/src/_pytest/pytester.py
index 953f776fdf..234dd98fcd 100644
--- a/src/_pytest/pytester.py
+++ b/src/_pytest/pytester.py
@@ -1427,7 +1427,7 @@ def run(
                 stdout=f1,
                 stderr=f2,
                 close_fds=(sys.platform != "win32"),
-                env=env
+                env=env,
             )
             if popen.stdin is not None:
                 popen.stdin.close()