E2ETes.js

/**
 * @jest-environment jsdom
 */
import app from "../server/app";
import puppeteer from "puppeteer";
import { opts } from "./helpers/util";
const PORT = 3032;
jest.setTimeout(60000);
let browser = null;
let instance = null

describe("Test container", function () {
    beforeAll(async () => {
        instance = app.listen(PORT);
        browser = await puppeteer.launch(opts);
    });

    afterAll(async () => {
        await browser.close();
        instance.close(() => { })
    });
  
    describe("E2E test", function () {
        it("Output script is being loaded and setting some_global_variable to 4",
            async function () {
                //  Arrange
                const page = await browser.newPage();
                let pageToLoad = `http://localhost:${PORT}/yourpage.html`              
                //   Act
                await page.goto(pageToLoad, { waitUntil: "networkidle0" });
                await page.waitForTimeout(2000);
                await scroll(page);
                await page.waitForTimeout(5000);
                let pageContextVariable = await page.evaluate(() => globalThis.some_global_variable);
                //  Assert
                expect(pageContextVariable).toBe(4);
                await page.close();
            });
    });

})

async function scroll(page) {
    await page.evaluate(() => {
        return new Promise((resolve, reject) => {
            var totalHeight = parseInt(0);
            var timer = setInterval(() => {
                let distance = 500
                var scrollHeight = document.body.scrollHeight;
                window.scrollBy(parseInt(0), distance);
                totalHeight += distance;
                if (totalHeight >= scrollHeight) {
                    clearInterval(timer);
                    resolve();
                }
            }, 200);
        });
    });
}