querySelector('#one');
        otherUrlElem = elems.querySelector('#two');
      });
      function assertHaveSameUrls(urlElemOne, urlElemTwo) {
        expect(urlElemOne.path).to.be.equal(urlElemTwo.path);
        expect(urlElemOne.hash).to.be.equal(urlElemTwo.hash);
        expect(urlElemOne.query).to.be.equal(urlElemTwo.query);
      }
      test('coordinate their changes (by firing events on window)', function() {
        assertHaveSameUrls(urlElem, otherUrlElem);

        urlElem.path = '/a/b/c';
     