This is a testharness.js-based test.
[FAIL] All properties (except 'all') can serialize their initial value (computed)
  assert_array_equals: lengths differ, expected array [] length 0, got [["grid", "none / none / none / row / auto / auto"], ["page-margin-safety", ""], ["page-orientation", ""], ["size", ""]] length 4
Harness: the test ran to completion.