'use strict'; require('../common'); const Readable = require('stream').Readable; const assert = require('assert'); const s = new Readable({ highWaterMark: 20, encoding: 'ascii' }); const list = ['1', '2', '3', '4', '5', '6']; s._read = function(n) { const one = list.shift(); if (!one) { s.push(null); } else { const two = list.shift(); s.push(one); s.push(two); } }; s.read(0); // ACTUALLY [1, 3, 5, 6, 4, 2] process.on('exit', function() { assert.deepStrictEqual(s._readableState.buffer.join(','), '1,2,3,4,5,6'); console.log('ok'); });