diff --git a/test-requirements.txt b/test-requirements.txt
index b2e4f9c1fd..7286fabd6d 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -4,3 +4,4 @@ hacking>=0.10,<0.11
 fixtures>=0.3.14
 testrepository>=0.0.18
 testtools>=0.9.36
+toposort>=1.0 # Apache 2.0