在React JS Jest测试中测试函数

function sum(a, b) {
  return a + b;
}

test('sum function should return the correct sum', () => {
  expect(sum(2, 3)).toBe(5);
  expect(sum(-1, 1)).toBe(0);
});

import { fetchData } from './api';

test('fetchData function should handle API response correctly', () => {
  const mockFetch = jest.fn(() => Promise.resolve({ data: 'mocked data' }));
  jest.mock('./api', () => ({ fetchData: mockFetch }));

  // Call the function that uses fetchData
  // ...

  expect(mockFetch).toHaveBeenCalledTimes(1);
  expect(mockFetch).toHaveBeenCalledWith(/* expected arguments */);
  // Expectations on the function that uses fetchData
  // ...
});

import { fetchData } from './api';

test('fetchData function should return the correct data', async () => {
  const data = await fetchData();
  expect(data).toEqual(/* expected data */);
});

// 或者使用 .resolves
test('fetchData function should return the correct data', () => {
  return expect(fetchData()).resolves.toEqual(/* expected data */);
});

import { shallow } from 'enzyme';
import MyComponent from './MyComponent';

test('MyComponent should render the correct content', () => {
  const wrapper = shallow(<MyComponent prop1="value1" prop2="value2" />);
  expect(wrapper.find('div')).toHaveLength(1);
  expect(wrapper.find('span')).toHaveLength(2);
  // Expectations on the rendered content
  // ...
});