diff --git a/requirements-test.txt b/requirements-test.txt
index b076a884..bc8c44d2 100644
--- a/requirements-test.txt
+++ b/requirements-test.txt
@@ -4,7 +4,7 @@ scrypt>=0.7.1
 secp256k1==0.13.2
 pytest==4.3.0
 coverage==4.5.2
-mock
+mock==2.0.0
 
 # Code style