diff --git a/requirements/testing.txt b/requirements/testing.txt
index c406f42daf2..e739e0d5194 100644
--- a/requirements/testing.txt
+++ b/requirements/testing.txt
@@ -5,6 +5,7 @@ pytest-django==3.1.2
 pytest-xdist==1.20.1
 apipkg==1.4
 execnet==1.5.0
+Mercurial==4.4.2
 
 # local debugging tools
 pdbpp