                this.attachShadow({mode: 'open'});
                this.shadowRoot.appendChild(document.importNode(template.content, true));
              }
            }
            if (connected) {
              connected.call(this);
            }
          }
        });
      };

      defineTestElement('x-h1', html`<div>shadow</div>`);

      defineTestElement('x-h2', html`<div><slot name="a"></slot></div>`);

      defineTestElement('x-inner1', html`<div><slot></slot></div>`);
      defineTestElement('