diff --git a/requirements/tests.txt b/requirements/tests.txt
index 4451d4f..feda1f0 100644
--- a/requirements/tests.txt
+++ b/requirements/tests.txt
@@ -1,5 +1,5 @@
 # latest version to validate behavior on pure python env
-pytest
+pytest==3.5.0
 # pytest-xdist  # for --boxed  # dropping this because of compat req with six...
 hypothesis
 numpy