diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 4adc53365..f1aa584c4 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -1,7 +1,11 @@
 name: test
 
 on:
+  # Every push onto the main branch triggers a retest.
   push:
+    branches:
+      - master
+  # All pull_requests trigger a retest.
   pull_request:
 
 jobs: