 lightDOMContent of ['','<span>light</span>']) {
        if (allowsShadowDom) {
          for (const declarativeShadowDom of [false, true]) {
            for (const delegatesFocus of [false, true]) {
              for (const clonable of [false, true]) {
                for (const mode of ['open', 'closed']) {
                  for (const serializable of [undefined, 'false', 'true']) {
                    for (const emptyShadowTree of [false, true]) {
                      testElementType(true, elementName, 