import { fireEvent, render, screen } from '@testing-library/react';
import { VirtualTreeViewport } from './VirtualTreeViewport';
describe('VirtualTreeViewport', () => {
  it('只渲染可视窗口并在滚动后更新行', () => {
    const items = Array.from({ length: 1000 }, (_, id) => ({ id, label: `节点 ${id}` }));
    render(
      <VirtualTreeViewport
        label="大型树"
        items={items}
        height={100}
        rowHeight={20}
        overscan={1}
        getKey={(item) => item.id}
        renderRow={(item) => <div>{item.label}</div>}
      />,
    );
    const tree = screen.getByRole('tree', { name: '大型树' });
    expect(screen.getByText('节点 0')).toBeVisible();
    expect(screen.queryByText('节点 500')).not.toBeInTheDocument();
    Object.defineProperty(tree, 'scrollTop', { configurable: true, value: 10000 });
    fireEvent.scroll(tree);
    expect(screen.getByText('节点 500')).toBeVisible();
    fireEvent.keyDown(tree, { key: 'ArrowDown' });
    expect(tree.getAttribute('aria-activedescendant')).toContain('501');
  });
});