diff --git a/test_requirements.txt b/test_requirements.txt
index 65a2fa7..882066a 100644
--- a/test_requirements.txt
+++ b/test_requirements.txt
@@ -1,4 +1,4 @@
-pytest
+pytest==3.1.1
 pytest-cov
 pytest-mock==1.1
 pytest-catchlog