chore: update example tests (#1126)

Remove some of the redundancy in the example tests

examples/protocol-and-stream-muxing/test-3.js

@@ -1,37 +1,14 @@
 'use strict'
 
 const path = require('path')
-const execa = require('execa')
-const pWaitFor = require('p-wait-for')
-const { toString: uint8ArrayToString } = require('uint8arrays/to-string')
+const { waitForOutput } = require('../utils')
 
-const messages = [
-  'from 1 to 2',
-  'from 2 to 1'
-]
-
-async function test() {
+async function test () {
   process.stdout.write('3.js\n')
 
-  let count = 0
-  const proc = execa('node', [path.join(__dirname, '3.js')], {
-    cwd: path.resolve(__dirname),
-    all: true
+  await waitForOutput('from 2 to 1', 'node', [path.join(__dirname, '3.js')], {
+    cwd: __dirname
   })
-
-  proc.all.on('data', async (data) => {
-    process.stdout.write(data)
-
-    const line = uint8ArrayToString(data)
-
-    if (messages.find((m) => line.includes(m))) {
-      count += 1
-    }
-  })
-
-  await pWaitFor(() => count === messages.length)
-
-  proc.kill()
 }
 
 module.exports = test