testRemoveCurrentDragItemClasses() {
    /** @suppress {checkTypes} suppression added to enable type checking */
    const be = new BrowserEvent({
      type: EventType.MOUSEDOWN,
      button: 0,
    });
    /**
     * @suppress {visibility,checkTypes} suppression added to enable type
     * checking
     */
    event.event_ = be;
    dlg.handlePotentialDragStart_(event);

    // Need to catch the dispatched event because the temporary fields
    // including dlg.currentDragItem_ are cleared after the dragging has ended.
    let currDragItem = dom.createDom(
        TagName.DIV, ['cursor_move', 'blue_bg'], dom.createTextNode('4'));
    events.listen(dlg, DragListGroup.EventType.DRAGEND, (e) => {
      /** @suppress {visibility} suppression added to enable type checking */
      currDragItem = dlg.currDragItem_;
    });

    /** @suppress {checkTypes} suppression added to enable type checking */
    const dragger = new Dragger(event.currentTarget);
    be.type = EventType.MOUSEUP;
    be.clientX = 1;
    be.clientY = 2;
    const dragEvent = new FxDragEvent(
        Dragger.EventType.END, dragger, be.clientX, be.clientY, be);
    dlg.handleDragEnd_(dragEvent);  // this method dispatches the DRAGEND event
    dragger.dispose();

    assertFalse(
        'Should have no cursor_move class after MOUSEUP',
        classlist.contains(currDragItem, 'cursor_move'));
    assertFalse(
        'Should have no cursor_pointer class after MOUSEUP',
        classlist.contains(currDragItem, 'cursor_pointer'));
    assertFalse(
        'Should have no opacity_40 class after MOUSEUP',
        classlist.contains(currDragItem, 'opacity_40'));
    assertFalse(
        'Should have no blue_bg class after MOUSEUP',
        classlist.contains(currDragItem, 'blue_bg'));
  }
Test the effect of dragging an item. (DRAGEND event.)
Check that after the MOUSEUP browser event handled by the handleDragEnd_()
method the currDragItem has no CSS classes set in the dispatched event.
@suppress {visibility} suppression added to enable type checking