diff --git a/tox.ini b/tox.ini
index 2ffdf06..45cc6df 100644
--- a/tox.ini
+++ b/tox.ini
@@ -17,6 +17,7 @@ deps =
   pytest-cov
   pytest-django
   pytest<4.1
+  attrs<19.2
   WebTest
   mock
   httmock