如何使用 mocha 和 chai 正确测试使用 axios.get 和 Cheerios.load 函数的 function？

Question

I have this index.js file

    const axios = require("axios");
    const cheerio = require('cheerio');

    const fetchData = async (webpage) => {
        const result = await axios.get(webpage);
        return cheerio.load(result.data);
    }
    const extractData = async (webPage) => {
        const $ = await fetchData(webPage);
        const numMains = $('.rank').text();
        //Should return the following string 
        //1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30.
        return numMains;
    }

    const siteUrl = "https://news.ycombinator.com/";

    (async (webPage) => {console.log(await extractData(webPage));})(siteUrl);

    module.exports = {
        extractData: extractData
    }

And I have this test.js file

    var chai = require('chai');
    var expect = chai.expect;
    var functionNames = require('../index.js');

    describe('extractData() Unit-Test', () => {
      it('This function should return a given string', () => {

        // 1. ARRANGE
        const siteUrl = "https://news.ycombinator.com/";
        const shouldResult = "1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30.";

        // 2. ACT
        const result = functionNames.extractData(siteUrl);

        // 3. ASSERT
        expect(result).to.be.equal(shouldResult);

      });
    });

*I'm not getting pass with this AssertionError: *

    AssertionError: expected {} to equal '1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30.'

Does someone know what I'm doing wrong and how can I solve this problem?

Answer 1

You're missing an await , you're comparing a Promise against 1,2,3 ...

it('This function should return a given string', async() => {

        // 1. ARRANGE
        const siteUrl = "https://news.ycombinator.com/";
        const shouldResult = "1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30.";

        // 2. ACT
        const result = await functionNames.extractData(siteUrl);

        // 3. ASSERT
        expect(result).to.be.equal(shouldResult);

});

Have in mind that you're actually performing the request while doing the test, if the site is down the test will fail. If you don't want that you can mock the request, using nock or a similar package.

Answer 2

As an alternative to Marcos's solution, you could also use eventually from chai:

result.should.eventually.equal(shouldResult);

Documentation here: https://www.chaijs.com/plugins/chai-as-promised/