diff --git a/noxfile.py b/noxfile.py
index f5e9967..e43d2ba 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -196,6 +196,7 @@ def test(session):
         'pytest',
         'pytest-cov',
         'pytest-env',
+        'pytest-mock',
         'pytest-randomly',
         'xdoctest[optional]',
     )