diff --git a/tools/generate-tempest-plugins-list.py b/tools/generate-tempest-plugins-list.py
index acb29af..8d26c25 100644
--- a/tools/generate-tempest-plugins-list.py
+++ b/tools/generate-tempest-plugins-list.py
@@ -65,7 +65,7 @@
 # json library won't choke.
 projects = sorted(filter(is_in_openstack_namespace, json.loads(r.text[4:])))
 
-found_plugins = filter(has_tempest_plugin, projects)
+found_plugins = list(filter(has_tempest_plugin, projects))
 
 # Every element of the found_plugins list begins with "openstack/".
 # We drop those initial 10 octets when printing the list.