Question

在测试我的ReactJs助手时，我找不到模拟对象导入的方法。那里的所有示例都显示了如何模拟导入的函数，没有人谈论模拟导入的对象。

我要模拟的基本帮助对象：

filters-state.helper.ts：

export const FiltersStateHelper = {
  toggleFilters: <T extends FiltersState>(state: T): T => ({
    ...state,
    isOpen: !state.isOpen
  })
};

我正在测试的状态助手中使用它：

search-view-state.helper.ts：

import { FiltersStateHelper } from 'shared/filters/helpers/filters-state.helper';

export const SearchViewStateHelper = {
  toggleFilters: <T extends SearchViewState>(state: T): T => ({
    ...state,
    filters: FiltersStateHelper.toggleFilters(state.filters)
  })
  //... more methods
};

在测试中，模拟依赖项失败了，可能是因为在我说出要模拟的内容之前，我的助手的依赖项已经解决：

search-view-state.helper.spec.ts：

import { SearchViewStateHelper as helper } from 'shared/search-view/helpers/search-view-state.helper';

describe('toggleFilters method', () => {
  const spy = jest.fn();
  jest.doMock('shared/filters/helpers/filters-state.helper', () => {
    return {
      toggleFilters: spy
    };
  });

  const state = {};

  it('should toggle filters', () => {
    helper.toggleFilters(state);
    expect(spy).toHaveBeenCalled();
  });
});

Answer 1

您可以使用jest.spyOn(object, methodName, accessType?)监视toggleFilters对象的FiltersStateHelper方法。

例如

filters-state.helper.ts：

type FiltersState = any;

export const FiltersStateHelper = {
  toggleFilters: <T extends FiltersState>(state: T): T => ({
    ...state,
    isOpen: !state.isOpen
  })
};

search-view-state.helper.ts：

import { FiltersStateHelper } from './filters-state.helper';

type SearchViewState = any;

export const SearchViewStateHelper = {
  toggleFilters: <T extends SearchViewState>(state: T): T => ({
    ...state,
    filters: FiltersStateHelper.toggleFilters(state.filters)
  })
  // ... more methods
};

search-view-state.helper.spec.ts：

import { SearchViewStateHelper as helper } from './search-view-state.helper';
import { FiltersStateHelper } from './filters-state.helper';

describe('toggleFilters method', () => {
  const state = { filters: { isOpen: false } };

  it('should toggle filters', () => {
    const spy = jest.spyOn(FiltersStateHelper, 'toggleFilters');
    helper.toggleFilters(state);
    expect(spy).toHaveBeenCalled();
    expect(spy).toBeCalledWith({ isOpen: false });
  });
});

覆盖率100％的单元测试结果：

 PASS  src/stackoverflow/58746881/search-view-state.helper.spec.ts
  toggleFilters method
    ✓ should toggle filters (6ms)

-----------------------------|----------|----------|----------|----------|-------------------|
File                         |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
-----------------------------|----------|----------|----------|----------|-------------------|
All files                    |      100 |      100 |      100 |      100 |                   |
 filters-state.helper.ts     |      100 |      100 |      100 |      100 |                   |
 search-view-state.helper.ts |      100 |      100 |      100 |      100 |                   |
-----------------------------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        3.833s, estimated 8s

源代码：https://github.com/mrdulin/jest-codelab/tree/master/src/stackoverflow/58746881

用笑话进行单元测试时如何模拟普通对象的依赖关系？

1 个答案: