diff --git a/tests/wpt/mozilla/tests/mozilla/calc.html b/tests/wpt/mozilla/tests/mozilla/calc.html
index 2408f196c00..80aa06e2ae7 100644
--- a/tests/wpt/mozilla/tests/mozilla/calc.html
+++ b/tests/wpt/mozilla/tests/mozilla/calc.html
@@ -144,7 +144,7 @@ var otherProperties = [
   ['border-spacing', 'calc(1px)', 'calc(1px)'],
   ['transform-origin', 'calc(1px + 0%)', 'calc(0% + 1px) center 0px'],
   ['perspective-origin', 'calc(1px + 0%)', 'calc(0% + 1px) center'],
-  ['background-size', 'calc(1px + 0%)', 'calc(0% + 1px) auto'],
+  ['background-size', 'calc(1px + 0%)', 'calc(0% + 1px)'],
   ['background-position', 'calc(1px + 0%) calc(2px + 0%)', 'calc(0% + 1px) calc(0% + 2px)'],
   ['border-top-left-radius', 'calc(1px + 0%)', 'calc(0% + 1px)'],
   ['border-bottom-left-radius', 'calc(1px + 0%)', 'calc(0% + 1px)'],