on x-foo and check localTarget and rootTarget', function() {
    var foo = app.$.foo;
    foo.dispatchEvent(new CustomEvent('click', {bubbles: true, composed: true}));
    assert.equal(app._testLocalTarget, app, 'local target');
    assert.equal(app._testRootTarget, foo, 'root target');
    let touches = [{
      clientX: 0,
      clientY: 0,
      identifier: 1,
      // target is set to the element with `addEventListener`, which is app
      target: app
    }];
    let touchstart = new CustomEvent('touchs