diff --git a/playbooks/zuul/run-base.yaml b/playbooks/zuul/run-base.yaml
index 40b3573cc5..661e687cb9 100644
--- a/playbooks/zuul/run-base.yaml
+++ b/playbooks/zuul/run-base.yaml
@@ -107,3 +107,6 @@
         name: tox
       vars:
         tox_envlist: testinfra
+        # This allows us to run from external projects (like testinfra
+        # itself)
+        zuul_work_dir: src/opendev.org/opendev/system-config