March 04, 2023 Adrian Matei (aka adixchen) Reading time ~1 minute

Override nested child element with spread operator in javascript

For the following req object there is a need to override the stackoverflowId attribute in a jest test

const req = {
  body: {
    _id: '123',
    name: 'Codever',
    location: 'https://www.codever.dev',
    language: 'en',
    description: 'This is a test bookmark',
    tags: ['test'],
    public: true,
    stackoverflowQuestionId: null
  },
  params: {
    userId: '456',
  },
};

Project: codever - File: bookmark-request.mapper.test.js

Here is how to achieve that with the spread operator

      {...req,
        body : {
        ...req.body,
          stackoverflowQuestionId: 123456
        }
      }

The complete function where this is used is shown below:

 test.each([
    [
      'should set stackoverflowQuestionId if it is provided',
      {...req,
        body : {
        ...req.body,
          stackoverflowQuestionId: 123456
        }
      },
      new Bookmark({
        _id: '123',
        name: 'Codever',
        location: 'https://www.codever.dev',
        language: 'en',
        description: 'This is a test bookmark',
        descriptionHtml: '<p>This is a test bookmark</p>',
        tags: ['test'],
        public: true,
        userId: '456',
        likeCount: 0,
        youtubeVideoId: null,
        stackoverflowQuestionId: 123456,
      })
    ],
  ])('%s', (testname, req, expectedBookmark) => {
    const resultBookmark = bookmarkRequestMapper.toBookmark(req);

    expect({...resultBookmark.toObject(), _id: {}}).toEqual({...expectedBookmark.toObject(), _id: {}});
    expect(showdown.Converter).toHaveBeenCalledTimes(1);
    expect(showdown.Converter().makeHtml).toHaveBeenCalledTimes(1);
    expect(showdown.Converter().makeHtml).toHaveBeenCalledWith('This is a test bookmark');
  });

Reference - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax

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March 03, 2023 Adrian Matei (aka adixchen) Reading time ~1 minute

An easy way to set test name in jest repetitive tests (test.each)

One easy way to display a custom name for each test.each test in jest, is to place the text name in the first element of each array of the input table for the method and use it as name in the test.each method - ('%s', (testname, req, expectedBookmark) , as in the following snippet:

const showdown = require('showdown');
const Bookmark = require('../../model/bookmark');
const bookmarkRequestMapper = require('./bookmark-request.mapper');

jest.mock('showdown', () => {
  const makeHtml = jest.fn(() => '<p>This is a test bookmark</p>');
  return {
    Converter: jest.fn().mockImplementation(() => ({makeHtml})),
  };
});

describe('toBookmark', () => {
  const req = {
    body: {
      _id: '123',
      name: 'Test Bookmark',
      location: 'https://example.com',
      language: 'en',
      description: 'This is a test bookmark',
      tags: ['test'],
      public: true,
    },
    params: {
      userId: '456',
    },
  };

  beforeEach(() => {
    showdown.Converter.mockClear();
    showdown.Converter().makeHtml.mockClear();
    req.body.descriptionHtml = undefined;
    req.body.youtubeVideoId = undefined;
    req.body.stackoverflowQuestionId = undefined;
  });

  test.each([
    [
      'should return a new bookmark',
      req,
      new Bookmark({
        _id: 123,
        name: 'Test Bookmark',
        location: 'https://example.com',
        language: 'en',
        description: 'This is a test bookmark',
        descriptionHtml: '<p>This is a test bookmark</p>',
        tags: ['test'],
        public: true,
        userId: '456',
        likeCount: 0,
        youtubeVideoId: null,
        stackoverflowQuestionId: null,
      })
    ],
    [
      'should set youtubeVideoId if it is provided',
      {...req,
        body : {
        ...req.body,
          youtubeVideoId: 'abcd1234'
        }
      },
      new Bookmark({
        _id: '123',
        name: 'Test Bookmark',
        location: 'https://example.com',
        language: 'en',
        description: 'This is a test bookmark',
        descriptionHtml: '<p>This is a test bookmark</p>',
        tags: ['test'],
        public: true,
        userId: '456',
        likeCount: 0,
        youtubeVideoId: 'abcd1234',
        stackoverflowQuestionId: null,
      })
    ],
    [
      'should set stackoverflowQuestionId if it is provided',
      {...req,
        body : {
        ...req.body,
          stackoverflowQuestionId: 123456
        }
      },
      new Bookmark({
        _id: '123',
        name: 'Test Bookmark',
        location: 'https://example.com',
        language: 'en',
        description: 'This is a test bookmark',
        descriptionHtml: '<p>This is a test bookmark</p>',
        tags: ['test'],
        public: true,
        userId: '456',
        likeCount: 0,
        youtubeVideoId: null,
        stackoverflowQuestionId: 123456,
      })
    ],
  ])('%s', (testname, req, expectedBookmark) => {
    const resultBookmark = bookmarkRequestMapper.toBookmark(req);

    expect({...resultBookmark.toObject(), _id: {}}).toEqual({...expectedBookmark.toObject(), _id: {}});
    expect(showdown.Converter).toHaveBeenCalledTimes(1);
    expect(showdown.Converter().makeHtml).toHaveBeenCalledTimes(1);
    expect(showdown.Converter().makeHtml).toHaveBeenCalledWith('This is a test bookmark');
  });
});

Project: codever - File: bookmark-request.mapper.test.js

Of course you are free to display other data where appropiate…

Reference - https://jestjs.io/docs/api#testeachtablename-fn-timeout

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March 02, 2023 Adrian Matei (aka adixchen) Reading time ~1 minute

Compare mongoose model objects in jest excluding _id

The schema model object in Mongoose provides an _id that is of type ObjectId. If you are not interested in comparing value of this attribute when you compare it compare objects in jest, you can exclude it by calling the toObject method of the mongoose model and set the _id object to nothing via the spread operator, something similar to the following:

expect({...resultBookmark.toObject(), _id: {}}).toEqual({...expectedBookmark.toObject(), _id: {}})

The complete testing method with the setup is shown in the snippet bellow, where expected bookmark model should match the mapped bookmark from the given request:

const showdown = require('showdown');
const Bookmark = require('../../model/bookmark');
const bookmarkRequestMapper = require('./bookmark-request.mapper');

jest.mock('showdown', () => {
  const makeHtml = jest.fn(() => '<p>This is a test bookmark</p>');
  return {
    Converter: jest.fn().mockImplementation(() => ({makeHtml})),
  };
});

describe('toBookmark', () => {
  const req = {
    body: {
      _id: '123',
      name: 'Test Bookmark',
      location: 'https://example.com',
      language: 'en',
      description: 'This is a test bookmark',
      tags: ['test'],
      public: true,
    },
    params: {
      userId: '456',
    },
  };

  beforeEach(() => {
    showdown.Converter.mockClear();
    showdown.Converter().makeHtml.mockClear();
    req.body.descriptionHtml = undefined;
    req.body.youtubeVideoId = undefined;
    req.body.stackoverflowQuestionId = undefined;
  });

  it('should use descriptionHtml if it is provided', () => {
    req.body.descriptionHtml = '<p>This is a test bookmark</p>';

    const expectedBookmark = new Bookmark({
      _id: '123',
      name: 'Test Bookmark',
      location: 'https://example.com',
      language: 'en',
      description: 'This is a test bookmark',
      descriptionHtml: '<p>This is a test bookmark</p>',
      tags: ['test'],
      public: true,
      userId: '456',
      likeCount: 0,
      youtubeVideoId: null,
      stackoverflowQuestionId: null,
    });

    const resultBookmark = bookmarkRequestMapper.toBookmark(req);

    expect({...resultBookmark.toObject(), _id: {}}).toEqual({...expectedBookmark.toObject(), _id: {}})
    expect(showdown.Converter().makeHtml).not.toHaveBeenCalled();
  });
});

Project: codever - File: bookmark-request.mapper.test.js

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February 14, 2023 Adrian Matei (aka adixchen) Reading time ~1 minute

Verify empty object with Jest (extended)

Install jest-extended (npm install --save-dev jest-extended) and use the toBeEmpty assertion as in the following example:

const { toBeEmpty } = require('jest-extended');
expect.extend({ toBeEmpty });

describe('setFulltextSearchTermsFilter', () => {
  test('returns filter without $text when fulltextSearchTerms is empty', () => {
    const fulltextSearchTerms = [];
    const filter = {};
    const searchInclude = 'any';
    expect(searchUtils.setFulltextSearchTermsFilter(fulltextSearchTerms, filter, searchInclude)).toBeEmpty();
  });
});

Use .toBeEmpty when checking if a String '', Array [], Object {}, or Iterable is empty. Because toBeEmpty supports checking for emptiness of Iterables, you can use it to check whether a Map, or Set is empty, as well as checking that a generator yields no values.

Project: codever - File: search.utils.spec.js

Reference - https://jest-extended.jestcommunity.dev/docs/matchers/tobeempty

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February 12, 2023 Adrian Matei (aka adixchen) Reading time ~2 minutes

How to run test.each tests in jest with async await

Method to test

Given the async/await function to find snippets on Codever

let findSnippets = async function (isPublic, userId, query, page, limit, searchInclude) {
  //split in text and tags
  const searchTermsAndTags = searchUtils.splitSearchQuery(query);
  const searchTerms = searchTermsAndTags.terms;
  const searchTags = searchTermsAndTags.tags;

  const {specialSearchTerms, fulltextSearchTerms} = searchUtils.extractFulltextAndSpecialSearchTerms(searchTerms);

  let filter = {}
  filter = searchUtils.setPublicOrPersonalFilter(isPublic, filter, userId);
  filter = searchUtils.setTagsToFilter(searchTags, filter);
  filter = searchUtils.setFulltextSearchTermsFilter(fulltextSearchTerms, filter, searchInclude);
  filter = searchUtils.setSpecialSearchTermsFilter(isPublic, userId, specialSearchTerms, filter);

  let snippets = await Snippet.find(
    filter,
    {
      score: {$meta: "textScore"}
    }
  )
    .sort({score: {$meta: "textScore"}})
    .skip((page - 1) * limit)
    .limit(limit)
    .lean()
    .exec();

  return snippets;
}

I would like verify if the filter is correctly set for different scenarios.

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Method to test