npm-networking/test/ws.test.mjs

// Connection-loss behaviour of the WS client, against a scripted fake socket.
// Run: npm test  (builds dist/ first, then `node --test test/`).
import { test, beforeEach, afterEach } from 'node:test'
import assert from 'node:assert/strict'
import { createWsClient } from '../dist/index.js'

// ── Fake WebSocket + tiny scripted server ──────────────────────────────────
class FakeWS extends EventTarget {
  static CONNECTING = 0
  static OPEN = 1
  static CLOSING = 2
  static CLOSED = 3
  /** Per connection attempt: 'accept' | 'fail' | 'hang' (opens, never established). */
  static plan = []
  static sockets = []
  /** event name → false to never answer it. */
  static answer = {}

  constructor(url) {
    super()
    this.url = url
    this.readyState = FakeWS.CONNECTING
    this.sent = []
    this.index = FakeWS.sockets.length
    FakeWS.sockets.push(this)
    const mode = FakeWS.plan[this.index] ?? 'accept'
    setTimeout(() => {
      if (this.readyState === FakeWS.CLOSED) return
      if (mode === 'fail') return this.drop()
      this.readyState = FakeWS.OPEN
      this.dispatchEvent(new Event('open'))
      if (mode === 'accept') this.push({ event: 'websocket.connection_established', data: JSON.stringify({ socket_id: `${this.index}.1` }) })
    }, 5)
  }

  send(raw) {
    const msg = JSON.parse(raw)
    this.sent.push(msg)
    const base = String(msg.event).replace(/\[.*\]$/, '')
    if (base === 'websocket.ping' || FakeWS.answer[base] === false) return
    if (FakeWS.answer[base] && FakeWS.answer[base] !== true && FakeWS.answer[base] !== this.index) return
    setTimeout(() => {
      if (this.readyState !== FakeWS.OPEN) return
      if (msg.event === 'websocket.subscribe') {
        this.push({ event: 'websocket.subscribe:response', data: { channel: msg.data.channel }, channel: msg.data.channel })
      } else {
        this.push({ event: msg.event + ':response', data: { ok: true, via: this.index }, channel: msg.channel })
      }
    }, 2)
  }

  close() {
    if (this.readyState === FakeWS.CLOSED) return
    this.readyState = FakeWS.CLOSED
    setTimeout(() => this.dispatchEvent(new Event('close')), 3)
  }

  /** Network failure: error + close. */
  drop() {
    this.readyState = FakeWS.CLOSED
    this.dispatchEvent(new Event('error'))
    this.dispatchEvent(new Event('close'))
  }

  push(obj) {
    this.dispatchEvent(new MessageEvent('message', { data: JSON.stringify(obj) }))
  }
}

const realWebSocket = globalThis.WebSocket
const clients = []

beforeEach(() => {
  FakeWS.plan = []
  FakeWS.sockets = []
  FakeWS.answer = {}
  globalThis.WebSocket = FakeWS
})

afterEach(() => {
  for (const c of clients.splice(0)) c.destroy()
  globalThis.WebSocket = realWebSocket
})

const client = (extra = {}) => {
  const c = createWsClient({
    url: 'ws://test/app/key',
    reconnectDelay: 20,
    reconnectThrottle: 40,
    heartbeatInterval: 60_000,
    showConnectionNotifications: false,
    ...extra,
  })
  clients.push(c)
  return c
}

const sleep = (ms) => new Promise((r) => setTimeout(r, ms))

/** Resolves to the value, or the string 'PENDING' if still unsettled after ms. */
const within = (p, ms = 800) => Promise.race([p, sleep(ms).then(() => 'PENDING')])

// ── Tests ───────────────────────────────────────────────────────────────────

test('baseline: a send resolves on a healthy connection', async () => {
  const ws = client()
  ws.setAppReady()
  const r = await within(ws.send('dash.index'))
  assert.deepEqual(r, { ok: true, via: 0 })
})

test('a send waiting on the app\'s first connect survives that attempt failing (setAppReady first)', async () => {
  // The app bootstraps the socket; pages send while it is still connecting.
  FakeWS.plan = ['fail', 'accept']
  const ws = client()
  ws.setAppReady()
  ws.connect().catch(() => {})
  const r = await within(ws.send('dash.index'))
  assert.deepEqual(r, { ok: true, via: 1 }, 'the send must not hang on the dropped connection promise')
  assert.equal(ws.is_setup.value, true)
})

test('a send after a failed connect that landed on the reconnect throttle still completes (connect before setAppReady)', async () => {
  FakeWS.plan = ['fail', 'accept']
  const ws = client()
  await ws.connect().catch(() => {}) // fails fast; no auto-reconnect yet (app not ready)
  ws.setAppReady()
  const r = await within(ws.send('dash.index'))
  assert.deepEqual(r, { ok: true, via: 1 }, 'a throttled connect must be retried, not dropped')
})

test('unchanged: a send that itself opens the connection rejects when that attempt fails', async () => {
  FakeWS.plan = ['fail', 'accept']
  const ws = client()
  ws.setAppReady()
  const r = await within(ws.send('dash.index').then(() => 'RESOLVED', (e) => e?.message))
  assert.equal(r, 'WebSocket error')
})

test('a forced reconnect is not undone by the old socket\'s late close event', async () => {
  const ws = client()
  ws.setAppReady()
  await within(ws.send('dash.index'))
  ws.last_reconnect_try = 0
  await ws.connect(true)
  await sleep(30) // the old socket's close event fires meanwhile
  assert.equal(ws.socket, FakeWS.sockets[1], 'the live socket must survive the stale close')
  const r = await within(ws.send('dash.index'))
  assert.deepEqual(r, { ok: true, via: 1 })
})

test('destroy() stays destroyed: the closing socket does not trigger an auto-reconnect', async () => {
  const ws = client()
  ws.setAppReady()
  await within(ws.send('dash.index'))
  ws.destroy()
  await sleep(80)
  assert.equal(FakeWS.sockets.length, 1, 'no new socket after destroy()')
})

test('a subscribe lost with its socket is retried on the next connection', async () => {
  FakeWS.plan = ['accept', 'accept']
  FakeWS.answer = { 'websocket.subscribe': 1 } // only socket #1 answers subscribes
  const ws = client()
  ws.setAppReady()
  const p = ws.send('dash.index')
  await sleep(30) // subscribe sent on socket #0, unanswered
  FakeWS.sockets[0].drop()
  const r = await within(p)
  assert.deepEqual(r, { ok: true, via: 1 })
})

test('rejectOnDisconnect: a send in flight on a dropped socket rejects with connection_lost', async () => {
  FakeWS.answer = { 'slow.call': false }
  const ws = client({ rejectOnDisconnect: true })
  ws.setAppReady()
  await within(ws.send('dash.index'))
  const p = ws.send('slow.call')
  await sleep(20)
  FakeWS.sockets[0].drop()
  const r = await within(p.then(() => 'RESOLVED', (e) => e))
  assert.equal(r?.code, 'connection_lost')
  assert.ok(typeof r?.message === 'string' && r.message.length > 0)
})

test('default (no rejectOnDisconnect): an in-flight send stays pending — behaviour unchanged', async () => {
  FakeWS.answer = { 'slow.call': false }
  const ws = client()
  ws.setAppReady()
  await within(ws.send('dash.index'))
  const p = ws.send('slow.call')
  await sleep(20)
  FakeWS.sockets[0].drop()
  assert.equal(await within(p, 150), 'PENDING')
})

test('sends queued while disconnected are delivered after the reconnect', async () => {
  const ws = client()
  ws.setAppReady()
  await within(ws.send('dash.index'))
  FakeWS.sockets[0].drop()
  const r = await within(ws.send('after.drop'))
  assert.deepEqual(r, { ok: true, via: 1 })
})

test('destroy() cancels an auto-reconnect that a drop had already scheduled', async () => {
  const ws = client()
  ws.setAppReady()
  await within(ws.send('dash.index'))
  FakeWS.sockets[0].drop() // schedules the auto-reconnect (reconnectDelay 20 ms)
  ws.destroy()
  await sleep(80)
  assert.equal(FakeWS.sockets.length, 1, 'no reconnect after destroy()')
})