From 48548767fcc1c65134309b649cf4d63f5b9cec65 Mon Sep 17 00:00:00 2001
From: Allan Feldman <allan.d.feldman@gmail.com>
Date: Wed, 21 Feb 2018 22:59:33 -0800
Subject: [PATCH] Use a frozen attr class for PseudoFixtureDef.

---
 _pytest/fixtures.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/_pytest/fixtures.py b/_pytest/fixtures.py
index 21fc32846..f9d0ef572 100644
--- a/_pytest/fixtures.py
+++ b/_pytest/fixtures.py
@@ -4,7 +4,7 @@ import functools
 import inspect
 import sys
 import warnings
-from collections import OrderedDict, deque, defaultdict, namedtuple
+from collections import OrderedDict, deque, defaultdict
 
 import attr
 import py
@@ -23,7 +23,11 @@ from _pytest.compat import (
 )
 from _pytest.outcomes import fail, TEST_OUTCOME
 
-PseudoFixtureDef = namedtuple('PseudoFixtureDef', ('cached_result', 'scope'))
+
+@attr.s(frozen=True)
+class PseudoFixtureDef(object):
+    cached_result = attr.ib()
+    scope = attr.ib()
 
 
 def pytest_sessionstart(session):