Nuxt/test/unit/async-config.size-limit.test.js

import cheerio from 'cheerio'
import fetch from 'node-fetch'
import { getPort, loadFixture, Nuxt } from '../utils'

let port
let nuxt = null
const url = route => 'http://localhost:' + port + route
let responseSizes

describe('size-limit test', () => {
  beforeAll(async () => {
    const options = await loadFixture('async-config')
    nuxt = new Nuxt(options)
    port = await getPort()
    await nuxt.server.listen(port, '0.0.0.0')

    const { html } = await nuxt.server.renderRoute('/')
    // Get all script URLs from the HTML
    const $ = cheerio.load(html)
    const scriptsUrls = $('script[src]')
      .map((_, el) => $(el).attr('src'))
      .get()
      .map(url)
    const resourceUrls = [url('/'), ...scriptsUrls]

    // Fetch all resources and get their size (bytes)
    responseSizes = await Promise.all(resourceUrls.map(async (url) => {
      const response = await fetch(url).then(res => res.text())
      return response.length
    }))
  })

  it('should stay within the size boundaries', () => {
    const responseSizeBytes = responseSizes.reduce((bytes, responseLength) => bytes + responseLength, 0)
    const responseSizeKilobytes = Math.ceil(responseSizeBytes / 1024)
    // Without gzip!
    expect(responseSizeKilobytes).toBeLessThanOrEqual(170)
  })
})