如何测试从 Jest 中的 Express 路由调用时类方法被调用一次

Question

我有一个班级Person.ts

export class Person {
  private name: string

  constructor(name) {
    this.name = name;
  }

  public getName = () => {
    return this.name;
  }
}

这个类被实例化，方法getName在我的路由器中被调用

router.post('/user', async (req, res) => {
  const person = new Person(req.body.name)
  const name = person.getName()

  res.json({
   name
  })
})

现在开玩笑

import request from "supertest"
import { Person } from "../person"

const getNameSpy = jest.spyOn(Person.prototype, "getName")

describe("User route", () => {
  it("Should return name", () => {
    await request(app).post("/user").send({ name: "john" })
    expect(getNameSpy).toHaveBeenCalledTimes(1)
  })
})

我收到这个错误

 Cannot spy on the getName property because it is not a function; undefined given instead. If you are trying to mock a property, use `jest.replaceProperty(object, 'getName', value)` instead.

我尝试过的其他事情

const mockGetName = jest.fn().mockReturnThis()
jest.mock("../person", () => {
  return {
    Person: jest.fn().mockImplementation(() => {
      return {
        getName: mockGetName
      }
    })
  }
})

describe("User route", () => {
  it("Should return name", () => {
    await request(app).post("/user").send({ name: "john" })
    expect(mockGetName).toHaveBeenCalledTimes(1)
  })
})

这也行不通。它返回

Expected number of calls: 1
Received number of calls: 0

你会怎么做？