LibTest/collection/DoubleLinkedQueue/skipWhile_A04_t01.dart

// Copyright (c) 2011, 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 Iterable<E> skipWhile(bool test(E value))
/// The returned iterable provides elements by iterating this iterable, but
/// skipping over all initial elements where [test(element)] returns [true]. If
/// all elements satisfy [test] the resulting iterable is empty, otherwise it
/// iterates the remaining elements in their original order, starting with the
/// first element for which [test(element)] returns [false].
/// @description Checks that once an element does not satisfy the [test],
/// the iterator stops testing and uses every element unconditionally.
/// @author kaigorodov

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

void check(List a0, bool test0(var element)) {
  DoubleLinkedQueue queue = new DoubleLinkedQueue.from(a0);
  bool? testPassed = null;
  bool test(var element) {
    Expect.isTrue(testPassed == null || testPassed!,
        "testPassed=$testPassed for element=$element");
    return testPassed =! test0(element);
  }
  for (var element in queue.skipWhile(test)) {
    Expect.isTrue(testPassed == null || !testPassed!);
  }  
}

main() {
  List a0 = [1, 3, 7, 4, 5, 6];
  check(a0, (var element) => element == 1);
  check(a0, (var element) => true);
  check(a0, (var element) => false);
  check(a0, (var element) => element > 4);
  check(a0, (var element) => element < 4);
  check(a0, (var element) => element == 4);
}