如果返回值是对象数组，如何编写通过的jest测试？

Question

我正在学习单元测试，并且我已经涵盖了大部分基础知识。

现在我正试着测试我的刮刀。我的初始函数涉及多个刮板，但我想检查每个刮板是否都能正常工作。测试的输出(为了测试成功)应该是如果返回有一个对象的[{},{},...,{}]数组。我真的不知道对象的内部是什么(数据总是不同的)，但它总是一个对象数组。

现在我的问题是:如何正确地做到这一点？我尝试过多种方法，但我的测试总是失败。下面是我一直以来的解决方案：

const santScraper = require('../scraping/scrapers/sant-scraper');

test('Does scraper works properly', async () => {
  await expect(santScraper(1)).toBe({});
});

但我的输出是：

FAIL  tests/santScraper.test.js
  × Does scraper works properly (20 ms)

  ● Does scraper works properly

    expect(received).toBe(expected) // Object.is equality

    - Expected  - 1
    + Received  + 1

    - Object {}
    + Promise {}

      2 |
      3 | test('Does scraper works properly', async () => {
    > 4 |   await expect(santScraper(1)).toBe({});
        |                                ^
      5 | });
      6 |

      at Object.<anonymous> (tests/santScraper.test.js:4:32)

Test Suites: 1 failed, 1 total
Tests:       1 failed, 1 total
Snapshots:   0 total
Time:        2.016 s
Ran all test suites.
npm ERR! Test failed.  See above for more details.

我真的不知道它指的是什么。

这也是我的刮刀：

//const data_functions = require('../data-functions/data-functions');
const axios = require('axios'); //npm package - promise based http client
const cheerio = require('cheerio'); //npm package - used for web-scraping in server-side implementations
const data_functions = require('../data-functions/data-functions');

//santScaper function which as paramater needs count which is sent in the scraping-service file.
const santScraper = async (count) => {
  const url = `https://www.sant.ba/pretraga/prodaja-1/tip-2/cijena_min-20000/stranica-${count}`;

  const santScrapedData = [];
  try {
    await load_url(url, santScrapedData);
  } catch (error) {
    console.log(error);
  }
};

//Function that does loading URL part of the scraper, and starting of process for fetching raw data.
const load_url = async (url, santScrapedData) => {
  await axios.get(url).then((response) => {
    const $ = cheerio.load(response.data);
    get_article_html_nodes($).each((index, element) => {
      process_single_article($, index, element, santScrapedData);
    });

    data_functions.mergeData(santScrapedData);
    return santScrapedData; //this is where I return array of objects
  });
};

// Part where raw html data is fetched but in div that we want.
const get_article_html_nodes = ($) => {
  return $('div[class="col-xxs-12 col-xss-6 col-xs-6 col-sm-6 col-lg-4"]');
};

//Here is all logic for getting data that we want, from the raw html.
const process_single_article = ($, index, element, santScrapedData) => {
  const getLink = $(element).find('a[class="re-image"]').attr('href');
  const getDescription = $(element).find('a[class="title"]').text();
  const getPrice = $(element)
    .find('div[class="prices"] > h3[class="price"]')
    .text()
    .replace(/\.| ?KM$/g, '')
    .replace(',', '.');
  const getPicture = $(element).find('img').attr('data-original');
  const getSquaremeters = $(element)
    .find('span[class="infoCount"]')
    .first()
    .text()
    .replace(',', '.')
    .split('m')[0];
  const pricepersquaremeter =
    parseFloat(getPrice) / parseFloat(getSquaremeters);

  santScrapedData[index] = {
    id: getLink.substring(42, 46),
    link: getLink,
    description: getDescription,
    price: Math.round(getPrice),
    picture: getPicture,
    squaremeters: Math.round(getSquaremeters),
    pricepersquaremeter: Math.round(pricepersquaremeter),
  };
};

module.exports = santScraper;

Answer 1

在这种情况下，您可以像这样使用typeof :-

test('Does scraper works properly', async () => {
  await expect(typeof santScraper(1)).toBe('object');
});

尽管如果它总是您想要检查的Promise对象，您可以使用instanceof获得更具体的内容，如下所示:-

test('Does scraper works properly', async () => {
  await expect(santScraper(1) instanceof Promise).toBe(true);
});