text: // Copyright Joyent, Inc. and other Node contributors.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a
  // copy of this software and associated documentation files (the
  // "Software"), to deal in the Software without restriction, including
  // without limitation the rights to use, copy, modify, merge, publish,
  // distribute, sublicense, and/or sell copies of the Software, and to permit
  // persons to whom the Software is furnished to do so, subject to the
  // following conditions:
  //
  // The above copyright notice and this permission notice shall be included
  // in all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
  // NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
  // DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  // USE OR OTHER DEALINGS IN THE SOFTWARE.
  
  'use strict';
  require('../common');
  const assert = require('assert');
  
  // This test verifies that stream.unshift(Buffer.alloc(0)) or
  // stream.unshift('') does not set state.reading=false.
  const Readable = require('stream').Readable;
  
  const r = new Readable();
  let nChunks = 10;
  const chunk = Buffer.alloc(10, 'x');
  
  r._read = function(n) {
    setImmediate(() => {
      r.push(--nChunks === 0 ? null : chunk);
    });
  };
  
  let readAll = false;
  const seen = [];
  r.on('readable', () => {
    let chunk;
    while (chunk = r.read()) {
      seen.push(chunk.toString());
      // simulate only reading a certain amount of the data,
      // and then putting the rest of the chunk back into the
      // stream, like a parser might do.  We just fill it with
      // 'y' so that it's easy to see which bits were touched,
      // and which were not.
      const putBack = Buffer.alloc(readAll ? 0 : 5, 'y');
      readAll = !readAll;
      r.unshift(putBack);
    }
  });
  
  const expect =
    [ 'xxxxxxxxxx',
      'yyyyy',
      'xxxxxxxxxx',
      'yyyyy',
      'xxxxxxxxxx',
      'yyyyy',
      'xxxxxxxxxx',
      'yyyyy',
      'xxxxxxxxxx',
      'yyyyy',
      'xxxxxxxxxx',
      'yyyyy',
      'xxxxxxxxxx',
      'yyyyy',
      'xxxxxxxxxx',
      'yyyyy',
      'xxxxxxxxxx',
      'yyyyy' ];
  
  r.on('end', () => {
    assert.deepStrictEqual(seen, expect);
    console.log('ok');
  });
  