diff --git a/etc/ci/manifest_changed.sh b/etc/ci/manifest_changed.sh
index c596239f3d0..f1bbf0de254 100755
--- a/etc/ci/manifest_changed.sh
+++ b/etc/ci/manifest_changed.sh
@@ -1,4 +1,5 @@
 #!/bin/bash
-diff=$(git diff -- tests/wpt/**/MANIFEST.json)
+./mach test-wpt --manifest-update SKIP_TESTS
+diff=$(git diff --exit-code -- tests/**/MANIFEST.json)
 echo "$diff"
 [[ ! $diff ]]