    assert.equal(collapse.opened, true);
      });
      
      test('verify height', function(done) {
        Polymer.flush();
        setTimeout(function() {
          collapseHeight = getCollapseComputedStyle().height;
          // verify height
          assert.notEqual(collapseHeight, '0px');
          done();
        }, delay);
      });
      
      test('test opened: false', function(done) {
        collapse.opened = false;
        Polymer.flush();
        setTimeout(function() {
          var h = g