如何模拟一个带参数的模块

Question

我正在尝试为使用 pg-promise 的代码编写单元测试，它看起来像这样：

const pgp = require('pg-promise')();

const cn = {
  host: process.env.DB_HOST,
  port: 5432,
  database: process.env.DB_NAME,
  user: process.env.DB_USER,
  password: process.env.DB_PASSWORD
};

function insertStuff(stuff) {
  let db = pgp(cn);
  return db.one('INSERT INTO test(stuff) VALUES () RETURNING id, stuff', [stuff])
    .then(data => {
      return data
    })
 }
 module.exports.insertStuff = insertStuff

测试代码如下所示：

const mockFakeDb = {
  one: jest.fn()
}

jest.mock("pg-promise", () => {
  return mockFakeDb
})

 const insertStuff = require("../src/db-utils").insertStuff

 test("params for inserting stuff are correct", done => {
   mockFakeDb.one.mockImplementationOnce(() => {
    return Promise.resolve({id: 123456789, stuff: "stuff"})

   insertStuff("stuff").then((data) => {
   const insertCall = fakeDb.one.mock.calls[0]
   expect(insertCall).toHaveBeenCalledTimes(1)
   done()
 })
})

因此在尝试模拟 pg-promise require 时出现错误：
TypeError: require(...) 不是函数。
我可以看到 pg-promise 有一个函数接受参数（第二个括号）但不确定现在如何模拟它？

Answer 1

对于其他不太确定如何执行此操作的人：

const fakeDB = {
  one: jest.fn()
}

function fakePgpFunc() {
  return fakeDB
}
fakePgpFunc.end = jest.fn()

jest.doMock("pg-promise", () => {
  return jest.fn(() => fakePgpFunc)
})

const insertStuff = require("../src/db-utils").insertStuff

beforeEach(() => {
  jest.clearAllMocks()
})

test("params for inserting stuff are correct", done => {
  fakeDB.one.mockImplementationOnce(() => {
    return Promise.resolve({"stuff": "Stuff", "id": 123456789})
  })

  insertStuff("Stuff").then((data) => {
    expect(fakeDB.one).toHaveBeenCalledTimes(1)
    const insertStuffCall = fakeDB.one.mock.calls[0]
    expect(insertStuffCall[0]).toEqual("INSERT INTO test(stuff) VALUES () RETURNING id, stuff")
    expect(queryInsertCall[1]).toEqual(["Stuff"])
    expect(data).toEqual({id: 123456789, stuff: "Stuff"})
    expect(fakePgpFunc.end).toHaveBeenCalledTimes(1)
    done()
  })
})

如何模拟一个带参数的模块

how to mock a module that takes a parameter

node.js

jestjs

pg-promise