diff --git a/tox.ini b/tox.ini
index c1051ce..daf186c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -21,7 +21,9 @@
   {posargs}
 
 [testenv:pin-digests]
+skip_install = true
 deps =
+  docker-image-py>=0.1.12
   oslo_config
   oslo_log
   ruyaml