Jest中的模拟处理方法

时间:2019-07-28 09:44:50

标签: javascript node.js unit-testing electron jestjs

我有electron-util.js个文件,我不想用测试进行介绍:

const isElectron = "electron" in process.versions;

const isUsingAsar =
  isElectron &&
  process.mainModule &&
  process.mainModule.filename.includes("app.asar");

export const fixPathForAsarUnpack = path =>
  isUsingAsar ? path.replace("app.asar", "app.asar.unpacked") : path;

为了测试fixPathForAsarUnpack方法,我需要从versions模拟mainModuleprocess。我试图这样做:

import { fixPathForAsarUnpack } from "../src/electron-util";

test("fixes path for Electron", () => {
  process.versions = {
    electron: "0.0.0",
    mainModule: {
      filename: "/app.asar/index.html"
    }
  };

  const path =
    "/Users/relix/My.app/Contents/Resources/app.asar/node_modules/foo/binary";

  expect(fixPathForAsarUnpack(path)).toBe(
    "/Users/relix/My.app/Contents/Resources/app.asar.unpack/node_modules/foo/binary"
  );
});

但是会引发错误:

  ● fixes path for Electron

    TypeError: Cannot assign to read only property 'versions' of object '[object process]'

      4 |
      5 | test("fixes path for Electron", () => {
    > 6 |   process.versions = {
        |   ^
      7 |     electron: "0.0.0",
      8 |     mainModule: {
      9 |       filename:

      at Object.<anonymous>.test (__test__/electron-util.test.js:6:3)

我在做什么错,我该如何模拟process对象?

1 个答案:

答案 0 :(得分:1)

您应该以这种方式模拟该过程:

const originalProcess = process
global.proces = {...originalProcess, version: "your code here"}
// do the test
// ...
// restore the original process object for next tests
global.process = originalProcess