如何脱离Jest使用prisma-mock模拟Prisma，为API控制器传入测试假数据？

核心逻辑 #

prisma-mock本质是生成一个模拟的Prisma Client实例，不需要绑定Jest测试框架，直接在Node.js环境初始化后注入到控制器即可，和你使用真实Prisma Client的方式完全一致。

具体实现步骤 #

1. 安装依赖 #

npm install prisma-mock @prisma/client

2. 初始化模拟Prisma并填充假数据 #

// mock-prisma.js
const { PrismaClient } = require('@prisma/client');
const { mockDeep } = require('prisma-mock');

// 创建模拟的Prisma Client实例
const mockPrisma = mockDeep(PrismaClient);

// 预定义假数据与查询逻辑
mockPrisma.user.findMany.mockResolvedValue([
  { id: 1, name: '张三', email: 'zhangsan@example.com' },
  { id: 2, name: '李四', email: 'lisi@example.com' }
]);

mockPrisma.user.findUnique.mockResolvedValue((args) => {
  return { id: args.where.id, name: `用户${args.where.id}`, email: `user${args.where.id}@test.com` };
});

// 模拟创建用户的逻辑（带内存数据持久化）
let mockUserId = 3;
mockPrisma.user.create.mockImplementation((args) => {
  const newUser = { id: mockUserId++, ...args.data };
  // 更新findMany的返回值，模拟数据新增
  const currentUsers = mockPrisma.user.findMany.mock.results[0]?.value || [];
  mockPrisma.user.findMany.mockResolvedValue([...currentUsers, newUser]);
  return Promise.resolve(newUser);
});

module.exports = mockPrisma;

3. 在API控制器中注入模拟实例 #

假设你的控制器代码如下：

// user-controller.js
class UserController {
  constructor(prisma) {
    this.prisma = prisma;
  }

  async getUsers(req, res) {
    const users = await this.prisma.user.findMany();
    res.status(200).json({ code: 200, data: users });
  }

  async getUserById(req, res) {
    const user = await this.prisma.user.findUnique({
      where: { id: parseInt(req.params.id) }
    });
    if (!user) return res.status(404).json({ code: 404, msg: '用户不存在' });
    res.status(200).json({ code: 200, data: user });
  }

  async createUser(req, res) {
    const newUser = await this.prisma.user.create({ data: req.body });
    res.status(201).json({ code: 201, data: newUser });
  }
}

module.exports = UserController;

在API服务中注入模拟Prisma实例：

// server.js
const express = require('express');
const UserController = require('./user-controller');
const mockPrisma = require('./mock-prisma');

const app = express();
app.use(express.json());

const userController = new UserController(mockPrisma);

app.get('/users', userController.getUsers.bind(userController));
app.get('/users/:id', userController.getUserById.bind(userController));
app.post('/users', userController.createUser.bind(userController));

app.listen(3000, () => {
  console.log('Mock API服务启动于端口3000');
});

4. 替代方案：手动模拟Prisma Client #

如果prisma-mock的使用不符合预期，也可以手动实现一个模拟类，完全复刻Prisma Client的方法签名：

// manual-mock-prisma.js
class MockPrisma {
  constructor() {
    this.userStore = [
      { id: 1, name: '张三', email: 'zhangsan@example.com' }
    ];
  }

  user = {
    findMany: () => Promise.resolve([...this.userStore]),
    findUnique: (args) => Promise.resolve(this.userStore.find(u => u.id === args.where.id)),
    create: (args) => {
      const newUser = { id: this.userStore.length + 1, ...args.data };
      this.userStore.push(newUser);
      return Promise.resolve(newUser);
    }
  };
}

module.exports = new MockPrisma();

直接在控制器中使用这个实例即可，调用方式和真实Prisma Client完全一致。

内容的提问来源于stack exchange，提问作者Dev