diff --git a/MANIFEST.in b/MANIFEST.in
index 62621c8f1..8d0c36caa 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -3,6 +3,7 @@ recursive-include docs *
 recursive-include scripts *
 recursive-include virtualenv_support *.whl
 recursive-include virtualenv_embedded *
+recursive-include tests *
 recursive-exclude docs/_templates *
 recursive-exclude docs/_build *
 include virtualenv_support/__init__.py