favela-surface-android / test / port-stability.test.js

// The surface port must survive a restart.
//
// ⛔ THE BUG THIS FIXES, SEEN ON THE HANDSET: "restart to apply" appeared to do nothing and the update
// banner looked frozen at the top of the page. The node HAD restarted and WAS serving the new bundle —
// logcat showed it booting the staged tree and reaching ready — but every boot bound a fresh ephemeral
// port, so the WebView was still pointing at the previous one. A dead URL renders the page it last
// loaded, which is indistinguishable from nothing having happened.
import test from 'brittle'
import http from 'bare-http1'
import { listenPreferring } from '../lib/node.js'

const close = (s) => new Promise((r) => s.close(r))

test('a remembered port is bound again', async (t) => {
  const a = http.createServer(() => {})
  await listenPreferring(a, 0)
  const port = a.address().port
  await close(a)

  const b = http.createServer(() => {})
  await listenPreferring(b, port)
  t.is(b.address().port, port, 'the same URL keeps working across a restart')
  await close(b)
})

test('a port someone else holds falls back instead of failing to boot', async (t) => {
  // Refusing to start over a port number would be a far worse failure than a changed URL.
  const squatter = http.createServer(() => {})
  await listenPreferring(squatter, 0)
  const taken = squatter.address().port

  const mine = http.createServer(() => {})
  await listenPreferring(mine, taken)
  t.ok(mine.address().port > 0, 'still bound')
  t.not(mine.address().port, taken, 'on a different port')

  await close(mine); await close(squatter)
})

test('port 0 still means any free port', async (t) => {
  const s = http.createServer(() => {})
  await listenPreferring(s, 0)
  t.ok(s.address().port > 0)
  await close(s)
})