diff --git a/.github/workflows/pythonpackage.yml b/.github/workflows/pythonpackage.yml
index d7ba1e1..2a87030 100644
--- a/.github/workflows/pythonpackage.yml
+++ b/.github/workflows/pythonpackage.yml
@@ -24,7 +24,8 @@ jobs:
             git+https://salsa.debian.org/python-debian-team/python-debian \
             "git+https://salsa.debian.org/debian/distro-info#subdirectory=python&egg=distro-info" \
             git+https://salsa.debian.org/jelmer/lintian-brush \
-            breezy
+            breezy \
+            testtools
         python setup.py develop
         mkdir -p ~/.config/breezy/plugins
         brz branch lp:brz-debian ~/.config/breezy/plugins/debian