LibTest/io/RandomAccessFile/truncateSync_A02_t01.dart

// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

// @dart = 2.9

/// @assertion void truncateSync(int length)
/// . . .
/// Throws a FileSystemException if the operation fails.
///
/// @description Checks that method truncateSync does not change the file length
/// if length is equal to the file length.
/// @author ngl@unipro.ru

import "dart:async";
import "dart:io";
import "../../../Utils/expect.dart";
import "../file_utils.dart";

main() {
  File file = getTempFileSync();
  asyncStart();
  Future<RandomAccessFile> raFile = file.open(mode: FileMode.write);
  raFile.then((RandomAccessFile rf) {
    Expect.isNotNull(rf);
    for (int i = 0; i < 10; i++) {
      rf.writeByteSync((i + 1) & 0xff);
    }
    rf.truncateSync(10);
    rf.closeSync();
    try {
      rf.truncateSync(10);
      Expect.fail("should not be here");
    } on Exception catch (e) {
      Expect.isTrue(e is FileSystemException);
    }
    asyncEnd();
  }).whenComplete(() {
    file.deleteSync();
  });
}