content: /*
   * Copyright 1999-2023 Alibaba Group Holding Ltd.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.alibaba.nacos.core.monitor.topn;
  
  import org.junit.jupiter.api.Test;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.Comparator;
  import java.util.List;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  class FixedSizePriorityQueueTest {
      
      @Test
      void testOfferEmpty() {
          FixedSizePriorityQueue<Integer> queue = new FixedSizePriorityQueue<>(10, Comparator.<Integer>naturalOrder());
          List<Integer> list = queue.toList();
          assertTrue(list.isEmpty());
      }
      
      @Test
      void testOfferLessThanSize() {
          FixedSizePriorityQueue<Integer> queue = new FixedSizePriorityQueue<>(10, Comparator.<Integer>naturalOrder());
          for (int i = 0; i < 5; i++) {
              queue.offer(i);
          }
          List<Integer> list = queue.toList();
          assertEquals(5, list.size());
          for (int i = 0; i < 5; i++) {
              assertTrue(list.contains(i));
          }
      }
      
      @Test
      void testOfferMoreThanSizeWithIncreasing() {
          FixedSizePriorityQueue<Integer> queue = new FixedSizePriorityQueue<>(10, Comparator.<Integer>naturalOrder());
          for (int i = 0; i < 15; i++) {
              queue.offer(i);
          }
          List<Integer> list = queue.toList();
          assertEquals(10, list.size());
          for (int i = 14; i > 4; i--) {
              assertTrue(list.contains(i));
          }
      }
      
      @Test
      void testOfferMoreThanSizeWithDecreasing() {
          FixedSizePriorityQueue<Integer> queue = new FixedSizePriorityQueue<>(10, Comparator.<Integer>naturalOrder());
          for (int i = 14; i > 0; i--) {
              queue.offer(i);
          }
          List<Integer> list = queue.toList();
          assertEquals(10, list.size());
          for (int i = 14; i > 4; i--) {
              assertTrue(list.contains(i));
          }
      }
      
      @Test
      void testOfferMoreThanSizeWithShuffle() {
          List<Integer> testCase = new ArrayList<>(50);
          for (int i = 0; i < 50; i++) {
              testCase.add(i);
          }
          Collections.shuffle(testCase);
          FixedSizePriorityQueue<Integer> queue = new FixedSizePriorityQueue<>(10, Comparator.<Integer>naturalOrder());
          testCase.forEach(queue::offer);
          List<Integer> list = queue.toList();
          assertEquals(10, list.size());
          for (int i = 49; i > 39; i--) {
              assertTrue(list.contains(i));
          }
      }
  }