Document clone should not re-execute javascript

• with mutating className541ms ‣

  this.timeout(10000);
  html2canvas(document.querySelector("#block")).then(function (canvas) {
      expect(canvas.width).to.equal(200);
      expect(canvas.height).to.equal(200);
      validCanvasPixels(canvas);
      done();
  }).catch(function (error) {
      done(error);
  });