node/test/parallel/test-stdin-script-child.js

'use strict';
const common = require('../common');
const assert = require('assert');

const { spawn } = require('child_process');
for (const args of [[], ['-']]) {
  const child = spawn(process.execPath, args, {
    env: Object.assign(process.env, {
      NODE_DEBUG: process.argv[2]
    })
  });
  const wanted = `${child.pid}\n`;
  let found = '';

  child.stdout.setEncoding('utf8');
  child.stdout.on('data', function(c) {
    found += c;
  });

  child.stderr.setEncoding('utf8');
  child.stderr.on('data', function(c) {
    console.error(`> ${c.trim().split('\n').join('\n> ')}`);
  });

  child.on('close', common.mustCall(function(c) {
    assert.strictEqual(c, 0);
    assert.strictEqual(found, wanted);
  }));

  setTimeout(function() {
    child.stdin.end('console.log(process.pid)');
  }, 1);
}