/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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 org.apache.commons.collections4;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import java.util.Comparator;
  
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests ComparatorUtils.
   */
  public class ComparatorUtilsTest {
  
      @Test
      public void testBooleanComparator() {
          Comparator<Boolean> comp = ComparatorUtils.booleanComparator(true);
          assertTrue(comp.compare(Boolean.TRUE, Boolean.FALSE) < 0);
          assertEquals(0, comp.compare(Boolean.TRUE, Boolean.TRUE));
          assertTrue(comp.compare(Boolean.FALSE, Boolean.TRUE) > 0);
  
          comp = ComparatorUtils.booleanComparator(false);
          assertTrue(comp.compare(Boolean.TRUE, Boolean.FALSE) > 0);
          assertEquals(0, comp.compare(Boolean.TRUE, Boolean.TRUE));
          assertTrue(comp.compare(Boolean.FALSE, Boolean.TRUE) < 0);
      }
  
      @Test
      public void testChainedComparator() {
          // simple test: chain 2 natural comparators
          final Comparator<Integer> comp = ComparatorUtils.chainedComparator(ComparatorUtils.<Integer>naturalComparator(),
                  ComparatorUtils.naturalComparator());
          assertTrue(comp.compare(1, 2) < 0);
          assertEquals(0, comp.compare(1, 1));
          assertTrue(comp.compare(2, 1) > 0);
      }
  
      @Test
      public void testMax() {
          final Comparator<Integer> reversed =
                  ComparatorUtils.reversedComparator(ComparatorUtils.<Integer>naturalComparator());
  
          assertEquals(Integer.valueOf(10), ComparatorUtils.max(1, 10, null));
          assertEquals(Integer.valueOf(10), ComparatorUtils.max(10, -10, null));
  
          assertEquals(Integer.valueOf(1), ComparatorUtils.max(1, 10, reversed));
          assertEquals(Integer.valueOf(-10), ComparatorUtils.max(10, -10, reversed));
  
          assertThrows(NullPointerException.class, () -> ComparatorUtils.max(1, null, null));
          assertThrows(NullPointerException.class, () -> ComparatorUtils.max(null, 10, null));
      }
  
      @Test
      public void testMin() {
          final Comparator<Integer> reversed =
                  ComparatorUtils.reversedComparator(ComparatorUtils.<Integer>naturalComparator());
  
          assertEquals(Integer.valueOf(1), ComparatorUtils.min(1, 10, null));
          assertEquals(Integer.valueOf(-10), ComparatorUtils.min(10, -10, null));
  
          assertEquals(Integer.valueOf(10), ComparatorUtils.min(1, 10, reversed));
          assertEquals(Integer.valueOf(10), ComparatorUtils.min(10, -10, reversed));
  
          assertThrows(NullPointerException.class, () -> ComparatorUtils.min(1, null, null));
          assertThrows(NullPointerException.class, () -> ComparatorUtils.min(null, 10, null));
      }
  
      @Test
      public void testNullHighComparator() {
          final Comparator<Integer> comp = ComparatorUtils.nullHighComparator(null);
          assertTrue(comp.compare(null, 10) > 0);
          assertEquals(0, comp.compare(null, null));
          assertTrue(comp.compare(10, null) < 0);
      }
  
      @Test
      public void testNullLowComparator() {
          final Comparator<Integer> comp = ComparatorUtils.nullLowComparator(null);
          assertTrue(comp.compare(null, 10) < 0);
          assertEquals(0, comp.compare(null, null));
          assertTrue(comp.compare(10, null) > 0);
      }
 }