diff --git a/setup.cfg b/setup.cfg
index 5da9e90..a54c476 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -45,6 +45,7 @@ namespace_packages =
 extra_files =
     setup.py
     README.rst
+    tests
 
 [wheel]
 # WSME has different requirements depending on the version of Python