function setUpRect () {
    setUp()
    elem = document.createElementNS(NS.SVG, 'rect')
    elem.setAttribute('x', '200')
    elem.setAttribute('y', '150')
    elem.setAttribute('width', '250')
    elem.setAttribute('height', '120')
    svg.append(elem)
  }
Initialize for tests and set up `rect` element.
@returns {void}