LibTest/async/Future/doWhile_A02_t03.dart

// Copyright (c) 2016, 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.

/// @assertion  Future doWhile(FutureOr<bool> f())
///    Perform an async operation repeatedly until it returns false.
/// . . .
///    If a future returned by f completes with an error, iteration ends and the
/// future returned by doWhile completes with the same error.
///
/// @description Checks that if f returns neither boolean nor Future, it is
/// a compile error
/// @issue #29202
/// @issue #29257
/// @author a.semenov@unipro.ru

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

const int N = 4;

main() {
  int num = 0;

  FutureOr<bool> f() {
    if (num == 2) throw "@";
    num++;
    return new Future.value(num < N);
  }

  asyncStart();
  Future.doWhile(f).then(
      (_) {
        Expect.fail("Returned future should fail with error");
      },
      onError: (e) {
        Expect.equals(2, num);
        asyncEnd();
      }
  );
}