ed.
  assert_equals(elem.getAttribute("style"), "z-index: 50; invalid",
                "style attribute after removing non-existing properties");
}, "Removing non-existing property or setting invalid value on CSS declaration block shouldn't queue mutation record");

test(function() {
  let elem = createTestElement("background-image: url(./);");
  let style = elem.style;
  let base = document.createElement("base");
  base.href = "/";
  document.body.appendChild(elem);
  let originalComputedValue = getComput