test-fs-write-file-sync.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
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
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'use strict';
const common = require('../common');

if (!common.isMainThread)
  common.skip('Setting process.umask is not supported in Workers');

const assert = require('assert');
const fs = require('fs');

// On Windows chmod is only able to manipulate read-only bit. Test if creating
// the file in read-only mode works.
const mode = common.isWindows ? 0o444 : 0o755;

// Reset the umask for testing
process.umask(0o000);

const tmpdir = require('../common/tmpdir');
tmpdir.refresh();

// Test writeFileSync
{
  const file = tmpdir.resolve('testWriteFileSync.txt');

  fs.writeFileSync(file, '123', { mode });
  const content = fs.readFileSync(file, { encoding: 'utf8' });
  assert.strictEqual(content, '123');
  assert.strictEqual(fs.statSync(file).mode & 0o777, mode);
}

// Test appendFileSync
{
  const file = tmpdir.resolve('testAppendFileSync.txt');

  fs.appendFileSync(file, 'abc', { mode });
  const content = fs.readFileSync(file, { encoding: 'utf8' });
  assert.strictEqual(content, 'abc');
  assert.strictEqual(fs.statSync(file).mode & mode, mode);
}

// Test writeFileSync with file descriptor
{
  // Need to hijack fs.open/close to make sure that things
  // get closed once they're opened.
  const _openSync = fs.openSync;
  const _closeSync = fs.closeSync;
  let openCount = 0;

  fs.openSync = (...args) => {
    openCount++;
    return _openSync(...args);
  };

  fs.closeSync = (...args) => {
    openCount--;
    return _closeSync(...args);
  };

  const file = tmpdir.resolve('testWriteFileSyncFd.txt');
  const fd = fs.openSync(file, 'w+', mode);

  fs.writeFileSync(fd, '123');
  fs.closeSync(fd);
  const content = fs.readFileSync(file, { encoding: 'utf8' });
  assert.strictEqual(content, '123');
  assert.strictEqual(fs.statSync(file).mode & 0o777, mode);

  // Verify that all opened files were closed.
  assert.strictEqual(openCount, 0);
  fs.openSync = _openSync;
  fs.closeSync = _closeSync;
}

// Test writeFileSync with flags
{
  const file = tmpdir.resolve('testWriteFileSyncFlags.txt');

  fs.writeFileSync(file, 'hello ', { encoding: 'utf8', flag: 'a' });
  fs.writeFileSync(file, 'world!', { encoding: 'utf8', flag: 'a' });
  const content = fs.readFileSync(file, { encoding: 'utf8' });
  assert.strictEqual(content, 'hello world!');
}

// Test writeFileSync with no flags
{
  const utf8Data = 'hello world!';
  for (const test of [
    { data: utf8Data },
    { data: utf8Data, options: { encoding: 'utf8' } },
    { data: Buffer.from(utf8Data, 'utf8').toString('hex'), options: { encoding: 'hex' } },
  ]) {
    const file = tmpdir.resolve(`testWriteFileSyncNewFile_${Math.random()}.txt`);
    fs.writeFileSync(file, test.data, test.options);

    const content = fs.readFileSync(file, { encoding: 'utf-8' });
    assert.strictEqual(content, utf8Data);
  }
}

// Test writeFileSync with an invalid input
{
  const file = tmpdir.resolve('testWriteFileSyncInvalid.txt');
  for (const data of [
    false, 5, {}, [], null, undefined, true, 5n, () => {}, Symbol(), new Map(),
    new String('notPrimitive'),
    { [Symbol.toPrimitive]: (hint) => 'amObject' },
    { toString() { return 'amObject'; } },
    Promise.resolve('amPromise'),
    common.mustNotCall(),
  ]) {
    assert.throws(
      () => fs.writeFileSync(file, data, { encoding: 'utf8', flag: 'a' }),
      { code: 'ERR_INVALID_ARG_TYPE' }
    );
  }
}