/*
    * 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.iterators;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  import java.util.NoSuchElementException;
  
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests the LoopingIterator class.
   */
  public class LoopingIteratorTest {
  
      /**
       * Tests constructor exception.
       */
      @Test
      public void testConstructorEx() {
          assertThrows(NullPointerException.class, () -> new LoopingIterator<>(null));
      }
  
      /**
       * Tests whether an empty looping iterator works as designed.
       */
      @Test
      public void testLooping0() {
          final List<Object> list = new ArrayList<>();
          final LoopingIterator<Object> loop = new LoopingIterator<>(list);
          assertFalse(loop.hasNext(), "hasNext should return false");
  
          assertThrows(NoSuchElementException.class, () -> loop.next(),
                  "NoSuchElementException was not thrown during next() call.");
      }
  
      /**
       * Tests whether a populated looping iterator works as designed.
       */
      @Test
      public void testLooping1() {
          final List<String> list = Arrays.asList("a");
          final LoopingIterator<String> loop = new LoopingIterator<>(list);
  
          assertTrue(loop.hasNext(), "1st hasNext should return true");
          assertEquals("a", loop.next());
  
          assertTrue(loop.hasNext(), "2nd hasNext should return true");
          assertEquals("a", loop.next());
  
          assertTrue(loop.hasNext(), "3rd hasNext should return true");
          assertEquals("a", loop.next());
      }
  
      /**
       * Tests whether a populated looping iterator works as designed.
       */
      @Test
      public void testLooping2() {
          final List<String> list = Arrays.asList("a", "b");
          final LoopingIterator<String> loop = new LoopingIterator<>(list);
  
          assertTrue(loop.hasNext(), "1st hasNext should return true");
          assertEquals("a", loop.next());
  
          assertTrue(loop.hasNext(), "2nd hasNext should return true");
          assertEquals("b", loop.next());
  
          assertTrue(loop.hasNext(), "3rd hasNext should return true");
          assertEquals("a", loop.next());
      }
  
      /**
       * Tests whether a populated looping iterator works as designed.
       */
      @Test
      public void testLooping3() {
          final List<String> list = Arrays.asList("a", "b", "c");
          final LoopingIterator<String> loop = new LoopingIterator<>(list);
 
         assertTrue(loop.hasNext(), "1st hasNext should return true");
         assertEquals("a", loop.next());
 
         assertTrue(loop.hasNext(), "2nd hasNext should return true");
         assertEquals("b", loop.next());
 
         assertTrue(loop.hasNext(), "3rd hasNext should return true");
         assertEquals("c", loop.next());
 
         assertTrue(loop.hasNext(), "4th hasNext should return true");
         assertEquals("a", loop.next());
     }
 
     /**
      * Tests the remove() method on a LoopingIterator wrapped ArrayList.
      */
     @Test
     public void testRemoving1() {
         final List<String> list = new ArrayList<>(Arrays.asList("a", "b", "c"));
         final LoopingIterator<String> loop = new LoopingIterator<>(list);
         assertEquals(3, list.size(), "list should have 3 elements.");
 
         assertTrue(loop.hasNext(), "1st hasNext should return true");
         assertEquals("a", loop.next());
         loop.remove();  // removes a
         assertEquals(2, list.size(), "list should have 2 elements.");
 
         assertTrue(loop.hasNext(), "2nd hasNext should return true");
         assertEquals("b", loop.next());
         loop.remove();  // removes b
         assertEquals(1, list.size(), "list should have 1 elements.");
 
         assertTrue(loop.hasNext(), "3rd hasNext should return true");
         assertEquals("c", loop.next());
         loop.remove();  // removes c
         assertEquals(0, list.size(), "list should have 0 elements.");
 
         assertFalse(loop.hasNext(), "4th hasNext should return false");
 
         assertThrows(NoSuchElementException.class, () -> loop.next(),
                 "Expected NoSuchElementException to be thrown.");
     }
 
     /**
      * Tests the reset() method on a LoopingIterator wrapped ArrayList.
      */
     @Test
     public void testReset() {
         final List<String> list = Arrays.asList("a", "b", "c");
         final LoopingIterator<String> loop = new LoopingIterator<>(list);
 
         assertEquals("a", loop.next());
         assertEquals("b", loop.next());
         loop.reset();
         assertEquals("a", loop.next());
         loop.reset();
         assertEquals("a", loop.next());
         assertEquals("b", loop.next());
         assertEquals("c", loop.next());
         loop.reset();
         assertEquals("a", loop.next());
         assertEquals("b", loop.next());
         assertEquals("c", loop.next());
     }
 
     /**
      * Tests the size() method on a LoopingIterator wrapped ArrayList.
      */
     @Test
     public void testSize() {
         final List<String> list = new ArrayList<>(Arrays.asList("a", "b", "c"));
         final LoopingIterator<String> loop = new LoopingIterator<>(list);
 
         assertEquals(3, loop.size());
         loop.next();
         loop.next();
         assertEquals(3, loop.size());
         loop.reset();
         assertEquals(3, loop.size());
         loop.next();
         loop.remove();
         assertEquals(2, loop.size());
     }
 
 }