diff --git a/setup.cfg b/setup.cfg
index 11cbe80..96001c0 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -33,7 +33,7 @@ include_package_data = True
 tests_require = pytest; typeguard; pygments; littleutils
 
 [options.extras_require]
-tests = pytest; typeguard; pygments; littleutils; cython
+tests = pytest; typeguard; pygments; littleutils; cython; setuptools
 
 [coverage:run]
 relative_files = True