test/parallel/test-file-write-stream.js

// Copyright Joyent, Inc. and other Node contributors.
//
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// following conditions:
//
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// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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'use strict';
const common = require('../common');
const assert = require('assert');

const fs = require('fs');
const tmpdir = require('../common/tmpdir');
const fn = tmpdir.resolve('write.txt');
tmpdir.refresh();
const file = fs.createWriteStream(fn, {
  highWaterMark: 10
});

const EXPECTED = '012345678910';

const callbacks = {
  open: -1,
  drain: -2,
  close: -1
};

file
  .on('open', common.mustCall((fd) => {
    console.error('open!');
    callbacks.open++;
    assert.strictEqual(typeof fd, 'number');
  }))
  .on('drain', common.mustCallAtLeast(() => {
    console.error('drain!', callbacks.drain);
    callbacks.drain++;
    if (callbacks.drain === -1) {
      assert.strictEqual(fs.readFileSync(fn, 'utf8'), EXPECTED);
      file.write(EXPECTED);
    } else if (callbacks.drain === 0) {
      assert.strictEqual(fs.readFileSync(fn, 'utf8'), EXPECTED + EXPECTED);
      file.end();
    }
  }))
  .on('close', common.mustCall(() => {
    console.error('close!');
    assert.strictEqual(file.bytesWritten, EXPECTED.length * 2);

    callbacks.close++;
    file.write('should not work anymore', common.expectsError({
      code: 'ERR_STREAM_WRITE_AFTER_END',
      name: 'Error',
      message: 'write after end'
    }));
    file.on('error', common.mustNotCall());

    fs.unlinkSync(fn);
  }));

for (let i = 0; i < 11; i++) {
  file.write(`${i}`);
}

process.on('exit', function() {
  for (const k in callbacks) {
    assert.strictEqual(callbacks[k], 0, `${k} count off by ${callbacks[k]}`);
  }
  console.log('ok');
});