/*
    * 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.Iterator;
  import java.util.NoSuchElementException;
  
  import org.apache.commons.collections4.ResettableIterator;
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests the SingletonIterator to ensure that the next() method will actually
   * perform the iteration rather than the hasNext() method.
   *
   * @param <E> the type of elements tested by this iterator.
   */
  public class SingletonIteratorTest<E> extends AbstractIteratorTest<E> {
  
      private static final Object testValue = "foo";
  
      /**
       * Returns a SingletonIterator from which
       * the element has already been removed.
       */
      @Override
      public SingletonIterator<E> makeEmptyIterator() {
          final SingletonIterator<E> iter = makeObject();
          iter.next();
          iter.remove();
          iter.reset();
          return iter;
      }
  
      @Override
      @SuppressWarnings("unchecked")
      public SingletonIterator<E> makeObject() {
          return new SingletonIterator<>((E) testValue);
      }
  
      @Override
      public boolean supportsEmptyIterator() {
          return true;
      }
  
      @Override
      public boolean supportsRemove() {
          return true;
      }
  
      @Test
      public void testIterator() {
          final Iterator<E> iter = makeObject();
          assertTrue(iter.hasNext(), "Iterator has a first item");
          final E iterValue = iter.next();
          assertEquals(testValue, iterValue, "Iteration value is correct");
          assertFalse(iter.hasNext(), "Iterator should now be empty");
          assertThrows(NoSuchElementException.class, iter::next);
      }
  
      @Test
      public void testReset() {
          final ResettableIterator<E> it = makeObject();
  
          assertTrue(it.hasNext());
          assertEquals(testValue, it.next());
          assertFalse(it.hasNext());
  
          it.reset();
  
          assertTrue(it.hasNext());
          assertEquals(testValue, it.next());
          assertFalse(it.hasNext());
  
          it.reset();
          it.reset();
  
          assertTrue(it.hasNext());
      }
  
      @Test
     @SuppressWarnings("unchecked")
     public void testSingletonIteratorRemove() {
         final ResettableIterator<E> iter = new SingletonIterator<>((E) "xyzzy");
         assertTrue(iter.hasNext());
         assertEquals("xyzzy", iter.next());
         iter.remove();
         iter.reset();
         assertFalse(iter.hasNext());
     }
 
 }