LibTest/collection/LinkedHashSet/LinkedHashSet_A05_t01.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.

// @dart = 2.9

/// @assertion LinkedHashMap({bool equals(K key1, K key2), int hashCode(K key),
/// bool isValidKey(potentialKey)})
/// If the [equals] or [hashCode] methods won't work on all objects, but only on
/// some instances of [E], the [isValidKey] predicate can be used to restrict the
/// keys that the functions are applied to. Any key for which [isValidKey]
/// returns false is automatically assumed to not be in the set when asking
/// [contains].
/// @description Checks that [isValidKey] is called before calling [equals] or
/// [hashCode]
/// @author sgrekhov@unipro.ru

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

bool checkDone = false;
bool isValidKeyCalled = false;

bool myEquals(var key1, var key2) {
  if (!checkDone) {
    Expect.isTrue(isValidKeyCalled);
    checkDone = true;
  }
  return key1 == key2;
}

int myHashCode(var key) {
  if (!checkDone) {
    Expect.isTrue(isValidKeyCalled);
    checkDone = true;
  }
  return key.hashCode;
}

bool isValidKey(var potentialKey) {
  isValidKeyCalled = true;
  return potentialKey is int;
}

reset() {
  checkDone = false;
  isValidKeyCalled = false;
}
skip() {
  isValidKeyCalled = true;
}

main() {
  LinkedHashSet set = new LinkedHashSet(equals: myEquals, hashCode: myHashCode,
      isValidKey: isValidKey);
  skip();
  set.add(1);

  reset();
  Expect.isTrue(set.contains(1));

  reset();
  Expect.isTrue(set.remove(1));

  reset();
  Expect.isFalse(set.contains(1));
}