'use strict'; const common = require('../common'); const assert = require('assert'); let bufsize = 0; switch (process.argv[2]) { case undefined: return parent(); case 'child': return child(); default: throw new Error('wtf?'); } function parent() { const spawn = require('child_process').spawn; const child = spawn(process.execPath, [__filename, 'child']); let sent = 0; let n = ''; child.stdout.setEncoding('ascii'); child.stdout.on('data', function(c) { n += c; }); child.stdout.on('end', common.mustCall(function() { assert.strictEqual(+n, sent); console.log('ok'); })); // Write until the buffer fills up. let buf; do { bufsize += 1024; buf = Buffer.alloc(bufsize, '.'); sent += bufsize; } while (child.stdin.write(buf)); // then write a bunch more times. for (let i = 0; i < 100; i++) { const buf = Buffer.alloc(bufsize, '.'); sent += bufsize; child.stdin.write(buf); } // now end, before it's all flushed. child.stdin.end(); // now we wait... } function child() { let received = 0; process.stdin.on('data', function(c) { received += c.length; }); process.stdin.on('end', function() { console.log(received); }); }