将jest mock封装在一个函数中，以便在多个测试中使用

// utils.js
export const fetchData = async (url) => {
  // 实际的数据获取逻辑
};

// testUtils.js
import { fetchData } from './utils';

export const createMockFetchData = (mockData) => {
  return jest.fn().mockImplementation((url) => {
    return Promise.resolve(mockData);
  });
};

// example.test.js
import { createMockFetchData } from './testUtils';
import { fetchData } from './utils';

test('example test', async () => {
  const mockData = { name: 'John' };
  const mockFetchData = createMockFetchData(mockData);
  fetchData.mockImplementation(mockFetchData);

  // 执行测试逻辑
});