diff --git a/requirements-tests.txt b/requirements-tests.txt
index 77b8736..c3bd786 100644
--- a/requirements-tests.txt
+++ b/requirements-tests.txt
@@ -1,4 +1,5 @@
 -r requirements.txt
+attrs==19.1.0
 pytest==3.4.2
 pytest-cov==2.6.0
 mock==2.0.0