From 50764d9ebbea4cd15717e49ba4ef4f467254a2be Mon Sep 17 00:00:00 2001
From: Andras Tim <andras.tim@gmail.com>
Date: Fri, 21 Jul 2017 21:27:48 +0200
Subject: [PATCH] Avoid interactive pdb when pytest tests itself - fix #2023

The debugging.py calls post_mortem() on error and pdb will drops an
interactive debugger when the stdin is a readable fd.
---
 _pytest/pytester.py   | 7 +++++--
 changelog/2023.bugfix | 1 +
 2 files changed, 6 insertions(+), 2 deletions(-)
 create mode 100644 changelog/2023.bugfix

diff --git a/_pytest/pytester.py b/_pytest/pytester.py
index 1783c9c0c..674adca94 100644
--- a/_pytest/pytester.py
+++ b/_pytest/pytester.py
@@ -916,8 +916,11 @@ class Testdir:
         env['PYTHONPATH'] = os.pathsep.join(filter(None, [
             str(os.getcwd()), env.get('PYTHONPATH', '')]))
         kw['env'] = env
-        return subprocess.Popen(cmdargs,
-                                stdout=stdout, stderr=stderr, **kw)
+
+        popen = subprocess.Popen(cmdargs, stdin=subprocess.PIPE, stdout=stdout, stderr=stderr, **kw)
+        popen.stdin.close()
+
+        return popen
 
     def run(self, *cmdargs):
         """Run a command with arguments.
diff --git a/changelog/2023.bugfix b/changelog/2023.bugfix
new file mode 100644
index 000000000..acf4b405b
--- /dev/null
+++ b/changelog/2023.bugfix
@@ -0,0 +1 @@
+Set ``stdin`` to a closed ``PIPE`` in ``pytester.py.Testdir.popen()`` for avoid unwanted interactive ``pdb``