diff --git a/.circleci/config.yml b/.circleci/config.yml
index aed85ffe567f610b1b46391f541cb78a3c47077c..ca9ac469a63e9f8463a593e4b3ef97ef7e86da98 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -121,7 +121,7 @@ jobs:
           name: "Test"
           command: |
             # And finally we can run the tests.
-            venv/bin/python -m twisted.trial _zkapauthorizer
+            venv/bin/python -m twisted.trial --rterrors _zkapauthorizer
 
   linux-tests:
     docker: