Pinned pytest to < 6.0

Pytest 6.0 breaks test collection on Python 3.5.

1 files changed, 1 insertions, 1 deletions

diff --git a/setup.py b/setup.py
index 65ce612..1531cb1 100644
--- a/setup.py
+++ b/setup.py
@@ -55,7 +55,7 @@ setup(
         'twisted': ['twisted'],
         'zookeeper': ['kazoo'],
         'testing': [
-            'pytest',
+            'pytest < 6',
             'pytest-cov',
             'pytest-tornado5'
         ],