heet.ownerNode, null);
  assert_equals(sheet.ownerRule, null);
  assert_equals(sheet.media.length, 2);
  assert_equals(sheet.media.item(0), "screen");
  assert_equals(sheet.media.item(1), "print");
  assert_true(sheet.disabled);
  assert_equals(sheet.cssRules.length, 0);

  sheet.insertRule(redStyleTexts[0]);
  assert_equals(sheet.cssRules.length, 1);
  assert_equals(sheet.cssRules[0].cssText, redStyleTexts[0]);

  sheet.insertRule(redStyleTexts[1]);
  assert_equals(sheet.cssRules.length, 2);
  assert_equal