test.js

import path from 'path'
import { fileURLToPath } from 'url'
import { execa } from 'execa'
import pDefer from 'p-defer'
import { toString as uint8ArrayToString } from 'uint8arrays/to-string'

const __dirname = path.dirname(fileURLToPath(import.meta.url))

function startProcess (name, args = []) {
  return execa('node', [path.join(__dirname, name), ...args], {
    cwd: path.resolve(__dirname),
    all: true
  })
}

let output1 = ''
let output2 = ''
let output3 = ''
let relayAddr
let autoRelayAddr

const proc1Ready = pDefer()
const proc2Ready = pDefer()

// Step 1 process
process.stdout.write('relay.js\n')

const proc1 = startProcess('relay.js')
proc1.all.on('data', async (data) => {
  process.stdout.write(data)

  output1 += uint8ArrayToString(data)

  if (output1.includes('Listening on:') && output1.includes('/p2p/')) {
    relayAddr = output1.trim().split('Listening on:\n')[1].split('\n')[0]
    proc1Ready.resolve()
  }
})

await proc1Ready.promise
process.stdout.write('==================================================================\n')

// Step 2 process
process.stdout.write('listener.js\n')

const proc2 = startProcess('listener.js', [relayAddr])
proc2.all.on('data', async (data) => {
  process.stdout.write(data)

  output2 += uint8ArrayToString(data)

  if (output2.includes('Advertising with a relay address of') && output2.includes('/p2p/')) {
    autoRelayAddr = output2.trim().split('Advertising with a relay address of ')[1].trim()
    proc2Ready.resolve()
  }
})

await proc2Ready.promise
process.stdout.write('==================================================================\n')

// Step 3 process
process.stdout.write('dialer.js\n')

const proc3 = startProcess('dialer.js', [autoRelayAddr])
proc3.all.on('data', async (data) => {
  process.stdout.write(data)

  output3 += uint8ArrayToString(data)

  if (output3.includes('Connected to the auto relay node via')) {
    const remoteAddr = output3.trim().split('Connected to the auto relay node via ')[1]

    if (remoteAddr === autoRelayAddr) {
      proc3.kill()
      proc2.kill()
      proc1.kill()
    } else {
      throw new Error('dialer did not dial through the relay')
    }
  }
})

await Promise.all([
  proc1,
  proc2,
  proc3
]).catch((err) => {
  if (err.signal !== 'SIGTERM') {
    throw err
  }
})