From 148e3c582afc6ae040d2ddcf09fade339a50dd1a Mon Sep 17 00:00:00 2001
From: Ran Benita <ran@unusedvar.com>
Date: Fri, 20 Nov 2020 17:50:58 +0200
Subject: [PATCH] pytester: always close stdin pipe in pytester.run()

If the user passed stdin=PIPE for some reason, they have no way to close
it themselves since it is not exposed.
---
 src/_pytest/pytester.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/_pytest/pytester.py b/src/_pytest/pytester.py
index e55b3ec1a..dd13ef4ce 100644
--- a/src/_pytest/pytester.py
+++ b/src/_pytest/pytester.py
@@ -1349,7 +1349,7 @@ class Pytester:
                 stderr=f2,
                 close_fds=(sys.platform != "win32"),
             )
-            if isinstance(stdin, bytes):
+            if popen.stdin is not None:
                 popen.stdin.close()
 
             def handle_timeout() -> None: