1 files changed, 3 insertions, 2 deletions
diff --git a/testing/web-platform/tests/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js b/testing/web-platform/tests/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
index 80c164f560..ad2119b738 100644
--- a/testing/web-platform/tests/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
+++ b/testing/web-platform/tests/html/browsers/browsing-the-web/back-forward-cache/resources/rc-helper.js
@@ -41,13 +41,14 @@ function sorted(s) {
   return Array.from(s).sort();
 }
 
-// Assert expected reasons and the reported reasons match.
+// Assert expected reasons are all present. Note that the extra reasons are allowed
+// as UAs might block bfcache for their specific reasons.
 function matchReasons(expectedNotRestoredReasonsSet, notRestoredReasonsSet) {
   const missing = setMinus(
     expectedNotRestoredReasonsSet, notRestoredReasonsSet, 'Missing reasons');
   const extra = setMinus(
       notRestoredReasonsSet, expectedNotRestoredReasonsSet, 'Extra reasons');
-  assert_true(missing.size + extra.size == 0, `Expected: ${sorted(expectedNotRestoredReasonsSet)}\n` +
+  assert_true(missing.size == 0, `Expected: ${sorted(expectedNotRestoredReasonsSet)}\n` +
     `Got: ${sorted(notRestoredReasonsSet)}\n` +
     `Missing: ${sorted(missing)}\n` +
     `Extra: ${sorted(extra)}\n`);