ReferenceError:无法在初始化前访问“jest_mock_extended_1”

Question

我有下面的代码。

singleton.ts

import prisma from "../prismaClient";
import { mockDeep, mockReset } from "jest-mock-extended";
import { PrismaClient } from "@prisma/client";
import { DeepMockProxy } from "jest-mock-extended/lib/cjs/Mock";

jest.mock("../prismaClient", () => ({
  __esModule: true,

  default: mockDeep<PrismaClient>(),
}));

beforeEach(() => {
  mockReset(prismaMock);
});

export const prismaMock = prisma as unknown as DeepMockProxy<PrismaClient>;

prismaClient.ts

import { PrismaClient } from "@prisma/client";

const prisma = new PrismaClient({
  log: [
    {
      emit: "event",
      level: "query",
    },
    {
      emit: "stdout",
      level: "error",
    },
    {
      emit: "stdout",
      level: "info",
    },
    {
      emit: "stdout",
      level: "warn",
    },
  ],
});

export default prisma;

我正在遵循prisma的单元测试指南：https://www.prisma.io/docs/guides/testing/unit-testing。我不知道为什么我总是犯这个错误：

此错误消息 ReferenceError:无法在初始化前访问“jest_mock_extended_1”

       7 |   __esModule: true,
       8 |
    >  9 |   default: mockDeep<PrismaClient>(),
         |            ^
      10 | }));
      11 |
      12 | beforeEach(() => {

      at src/utils/testUtils/singleton.ts:9:12
      at Object.<anonymous> (src/utils/testUtils/singleton.ts:1:1)
      at Object.<anonymous> (src/resolvers/functions/user.test.ts:1:1)

Answer 1

问题是导入路径和您正在模拟的路径是相同的。那就是import prisma from "../prismaClient";被嘲笑

jest.mock("../prismaClient", () => ({
  __esModule: true,

  default: mockDeep<PrismaClient>(),
}));

因此，这意味着在文件本身中会发生模拟，从而触发该错误。如果您想让它工作，那么您正在嘲笑的路径和您在这里导入的路径必须不同。像下面这样的东西起作用

import prisma from "../prismaClient";

jest.mock("../../prismaClient", () => ({
  __esModule: true,

  default: mockDeep<PrismaClient>(),
}));

Answer 2

导入一个类似乎很奇怪，而您只是为了导出它而对其进行模拟。因此，我创建了deepMock of PrismaClient，将其添加到jest.mock并导出了deepMock。

import { PrismaClient } from '@prisma/client'
import { mockDeep, mockReset, DeepMockProxy } from 'jest-mock-extended'

const prismaMock = mockDeep<PrismaClient>();

jest.mock("../prismaClient", () => ({
  __esModule: true,
  default: prismaMock
}));

beforeEach(() => {
  mockReset(prismaMock);
});

export { prismaMock }