Run similar tests with Mocha

Question

Background

I am scrapping a wikia for information, and before I actually do that, I wanna make sure I can connect to the wikia servers.

Best way to do it? Using mocha tests with my nodejs app!

Objective

I have a configuration file, which has an object with all the links I want. I have a battery set called "connection" and I want each test to try to connect to the wikia.

{
    "sources": {
        "wikia": {
            "link": "http://warframe.wikia.com/wiki",
            "pages": {
                "mods_2.0": "/Mods_2.0",
                "warframe_mods": "/Category:Warframe_Mods",
                //more links follow
            }
        }
    }
}

Problem

The problem here is that I don't want to write and replicate the same test for over a dozen wikia pages. I want to avoid repetition.

My solution to this, was to put every it inside a loop, however, the code breaks because my wikiaPages arrays is always undefined, even when I use the before() function.

Code

let assert = require("assert");
let superagent = require("superagent");
let jsonfile = require("jsonfile");

const SCRAPER_CONFIG_FILE = "./scraperConfig.json";

describe("connection", () => {

    let wikiaUri;
    let wikiaPages;
    let completeUri;

    before(() => {
        let config = jsonfile.readFileSync(SCRAPER_CONFIG_FILE);
        wikiaUri = config.sources.wikia.link;
        wikiaPages = Object.values(config.sources.wikia.pages);
    });

    for(let pageUri of wikiaPages) {

        completeUri = wikiaUri + pageUri;

        it("connects to " + completeUri, done => {
            superagent.get(completeUri, (error, res) => {
                assert.ifError(error);
                assert.equal(res.status, 200);
                done();
            });
        });
    }
});

Questions

• How can I fix this code, so it works?

Answer 1

move it out of your before block:

describe("connection", () => {
    const config = jsonfile.readFileSync(SCRAPER_CONFIG_FILE);
    const wikiaUri = config.sources.wikia.link;
    const wikiaPages = Object.values(config.sources.wikia.pages);

    before(() => {
    });

    for(let pageUri of wikiaPages) {

        completeUri = wikiaUri + pageUri;

        it("connects to " + completeUri, done => {
            superagent.get(completeUri, (error, res) => {
                assert.ifError(error);
                assert.equal(res.status, 200);
                done();
            });
        });
    }
});

Answer 2

That's because your loop wikiaPages happens on declaration stage, which is before before stage, so wikiaPages is not yet assigned a value.

Unwrapping before hook so reading config file and setting it s happens on declaration stage should make it work:

let assert = require("assert");
let superagent = require("superagent");
let jsonfile = require("jsonfile");

const SCRAPER_CONFIG_FILE = "./scraperConfig.json";

describe("connection", () => {

    let wikiaUri;
    let wikiaPages;
    let completeUri;


    let config = jsonfile.readFileSync(SCRAPER_CONFIG_FILE);
    wikiaUri = config.sources.wikia.link;
    wikiaPages = Object.values(config.sources.wikia.pages);

    for(let pageUri of wikiaPages) {

        completeUri = wikiaUri + pageUri;

        it("connects to " + completeUri, done => {
            superagent.get(completeUri, (error, res) => {
                assert.ifError(error);
                assert.equal(res.status, 200);
                done();
            });
        });
    }
});