diff --git a/setup.py b/setup.py
index 0824491..57322c2 100755
--- a/setup.py
+++ b/setup.py
@@ -58,7 +58,7 @@ setuptools.setup(
         license='GPL',
         packages=['warcprox'],
         install_requires=deps,
-        tests_require=['requests>=2.0.1', 'pytest'],  # >=2.0.1 for https://github.com/kennethreitz/requests/pull/1636
+        tests_require=['requests>=2.0.1', 'pytest', 'warcio'],  # >=2.0.1 for https://github.com/kennethreitz/requests/pull/1636
         cmdclass = {'test': PyTest},
         test_suite='warcprox.tests',
         entry_points={