('#container');
            let newDiv = div.cloneNode(true);
            let span = document.createElement('span');
            span.textContent = 'created dynamically';
            newDiv.appendChild(span);
            this.shadowRoot.appendChild(newDiv);
            requestAnimationFrame(() => {
              assert.equal(
                getComputedStyle(span).backgroundColor,
                'rgb(123, 123, 123)'
              );
              done();
            });
          });
        });
        te