Question

我正在尝试用笑话来测试localStorage：

    it("changes the localStorage", () => {
      const changeLocale = (languageLocale) => {
        localStorage.setItem("language", languageLocale);
        return {
          type: "CHANGE_LOCALE",
          locale: languageLocale
        };
      }


      const locale = "de";

      localStorage.clear();

      changeLocale(locale);

      expect(localStorage.setItem).toHaveBeenLastCalledWith(LOCAL_LANG, locale);
      expect(localStorage.__STORE__[LOCAL_LANG]).toBe(locale);
    });

当我尝试使用npm run test运行它时，它返回如下错误：

expect(jest.fn())[.not].toHaveBeenLastCalledWith()

jest.fn() value must be a mock function or spy.
Received:
  function: [Function setItem]

  33 |       changeLocale(locale);
  34 |
> 35 |       expect(localStorage.setItem).toHaveBeenLastCalledWith(LOCAL_LANG, locale);
     |                                    ^
  36 |       expect(localStorage.__STORE__[LOCAL_LANG]).toBe(locale);
  37 |     });
  38 |   });

我使用jest-localstorage-mock。您能否指出为什么我会收到该错误？谢谢。

Answer 1

我决定摆脱jest-localstorage-mock的用法。相反，我这样做是spyOn：

jest.spyOn(Storage.prototype, 'setItem');
jest.spyOn(Storage.prototype, 'getItem');

因此整个解决方案如下：

it('changes the localStorage', () => {
  const changeLocale = languageLocale => {
    localStorage.setItem('language', languageLocale);
    return {
      type: 'CHANGE_LOCALE',
      locale: languageLocale
    };
  }

  const locale = 'de';

  jest.spyOn(Storage.prototype, 'setItem');
  jest.spyOn(Storage.prototype, 'getItem');

  localStorage.clear();

  changeLocale(locale);

  expect(localStorage.setItem).toHaveBeenLastCalledWith(LOCAL_LANG, locale);
  expect(localStorage.getItem(LOCAL_LANG)).toBe(locale);
});

希望对某人有帮助：）

笑话和本地存储

1 个答案: