celler();
  });

  test('tap', function() {
    var ev = new CustomEvent('mousedown', {
      bubbles: true,
      cancelable: true,
      composed: true
    });
    el.dispatchEvent(ev);
    assert.equal(el.stream.length, 1, 'one event dispatched');
    assert.equal(el.stream[0].type, 'down', 'was down event');
    assert.equal(el.stream[0].defaultPrevented, true, 'was prevented');
    assert.equal(ev.defaultPrevented, true, 'base event was prevented');
  });

  test('track', function() {
    var ev = new 