如何用Jest模拟另一个函数内部的函数

// functions.js
export function getPrice(item) {
  // 假设这是一个复杂的计算
  return item.price * item.quantity;
}

export function calculateTotal(items) {
  let total = 0;
  for (const item of items) {
    total += getPrice(item);
  }
  return total;
}

// functions.test.js
import { calculateTotal, getPrice } from './functions';

jest.mock('./functions', () => {
  return {
    ...jest.requireActual('./functions'),
    getPrice: jest.fn(),
  };
});

describe('calculateTotal', () => {
  it('should calculate the total correctly', () => {
    const items = [
      { price: 10, quantity: 2 },
      { price: 5, quantity: 3 },
    ];

    // 模拟 getPrice 函数的行为
    getPrice.mockImplementation((item) => item.price * item.quantity);

    const result = calculateTotal(items);
    expect(result).toBe(35);

    // 验证 getPrice 函数是否被正确调用
    expect(getPrice).toHaveBeenCalledTimes(2);
    expect(getPrice).toHaveBeenCalledWith({ price: 10, quantity: 2 });
    expect(getPrice).toHaveBeenCalledWith({ price: 5, quantity: 3 });
  });
});