diff --git a/setup.py b/setup.py
index c2406240..3e0f1555 100755
--- a/setup.py
+++ b/setup.py
@@ -47,7 +47,7 @@ packages = [
 ]
 
 requires = []
-test_requirements = ['pytest>=2.8.0', 'pytest-httpbin==0.0.7', 'pytest-cov']
+test_requirements = ['pytest>=2.8.0', 'pytest-httpbin==0.0.7', 'pytest-cov', 'pytest-mock']
 
 with open('requests/__init__.py', 'r') as fd:
     version = re.search(r'^__version__\s*=\s*[\'"]([^\'"]*)[\'"]',