diff --git a/tox.ini b/tox.ini
index be02d5b51..5320733e5 100644
--- a/tox.ini
+++ b/tox.ini
@@ -30,6 +30,7 @@ commands =
          pyflakes src static misc setup.py
          tahoe --version
          coverage run --branch -m allmydata.test.run_trial --rterrors --reporter=timing {posargs:allmydata}
+         coverage xml
 
 [testenv:codechecks]
 passenv = USERPROFILE HOMEDRIVE HOMEPATH