docs/tests/rendering/robots-txt.js

const languages = require('../../lib/languages')
const robotsParser = require('robots-parser')
const robotsMiddleware = require('../../middleware/robots')
const { get } = require('../helpers/supertest')
const MockExpressResponse = require('mock-express-response')

describe('robots.txt', () => {
  jest.setTimeout(5 * 60 * 1000)

  let res, robots
  beforeAll(async (done) => {
    res = await get('/robots.txt')
    robots = robotsParser('https://docs.github.com/robots.txt', res.text)
    done()
  })

  it('allows indexing of the homepage and English content', async () => {
    expect(robots.isAllowed('https://docs.github.com/')).toBe(true)
    expect(robots.isAllowed('https://docs.github.com/en')).toBe(true)
    expect(robots.isAllowed('https://docs.github.com/en/articles/verifying-your-email-address')).toBe(true)
  })

  it('allows indexing of generally available localized content', async () => {
    Object.values(languages)
      .filter(language => !language.wip)
      .forEach(language => {
        expect(robots.isAllowed(`https://docs.github.com/${language.code}`)).toBe(true)
        expect(robots.isAllowed(`https://docs.github.com/${language.code}/articles/verifying-your-email-address`)).toBe(true)
      })
  })

  it('disallows indexing of herokuapp.com domains', async () => {
    const req = {
      hostname: 'docs-internal-12345--my-branch.herokuapp.com',
      path: '/robots.txt'
    }
    const res = new MockExpressResponse()
    const next = () => { /* no op */ }

    await robotsMiddleware(req, res, next)
    expect(res._getString()).toEqual('User-agent: *\nDisallow: /')
  })

  it('does not have duplicate lines', () => {
    const lines = new Set()
    for (const line of res.text.split('\n')) {
      if (/^\s*$/.test(line)) continue
      expect(lines.has(line)).toBe(false)
      lines.add(line)
    }
  })
})