index", "41");
  assert_record_with_old_value("z-index: 40;", "changing property in CSS declaration block");
  style.cssText = "z-index: 42;";
  assert_record_with_old_value("z-index: 41;", "changing cssText");
  style.cssText = "z-index: 42;";
  assert_record_with_old_value("z-index: 42;", "changing cssText with the same content");
  style.removeProperty("z-index");
  assert_record_with_old_value("z-index: 42;", "removing property from CSS declaration block");
  // Mutation to shorthand properties should a