// Copyright (c) 2019, 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 To handle these gracefully, we support a [...?] "null-aware
/// spread" operator. In cases where the spread expression evaluates to [null],
/// that expands to an empty collection instead of throwing a runtime expression.
///
///  That turns the example to:
///
///   var command = [
///   engineDartPath,
///   '--target=flutter',
///   ...?extraFrontEndOptions,
///   mainPath
///   ];
/// @description Checks that exception is thrown if spreadable element in the
/// [Set] is not null-aware and it's [null].
/// @author iarkh@unipro.ru


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

Set getASet(
    String engineDartPath, List extraFrontEndOptions, String mainPath) {
  return(
      {engineDartPath, '--target=flutter', ...extraFrontEndOptions, mainPath});
}

main() {
  Set a;

  Expect.setEquals({"enginePath", "--target=flutter", "--option1", "mainPath"},
      getASet("enginePath", ["--option1"], "mainPath"));

  Expect.throws(() => a = getASet("enginePath", null, "mainPath"));
}