/*
    * 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.set;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.Set;
  
  import org.apache.commons.collections4.collection.AbstractCollectionTest;
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests {@link Set}.
   * <p>
   * Since {@link Set} doesn't stipulate much new behavior that isn't already
   * found in {@link Collection}, this class basically just adds tests for
   * {@link Set#equals} and {@link Set#hashCode()} along with an updated
   * {@link #verify()} that ensures elements do not appear more than once in the
   * set.
   * <p>
   * To use, subclass and override the {@link #makeObject()}
   * method.  You may have to override other protected methods if your
   * set is not modifiable, or if your set restricts what kinds of
   * elements may be added; see {@link AbstractCollectionTest} for more details.
   */
  public abstract class AbstractSetTest<E> extends AbstractCollectionTest<E> {
  
      /**
       * Gets the {@link AbstractCollectionTest#collection} fixture, but cast as a Set.
       */
      @Override
      public Set<E> getCollection() {
          return (Set<E>) super.getCollection();
      }
  
      /**
       * Gets the {@link AbstractCollectionTest#confirmed} fixture, but cast as a Set.
       */
      @Override
      public Set<E> getConfirmed() {
          return (Set<E>) super.getConfirmed();
      }
  
      /**
       * Sets equals method is defined.
       */
      @Override
      public boolean isEqualsCheckable() {
          return true;
      }
  
      /**
       * Returns an empty Set for use in modification testing.
       *
       * @return a confirmed empty collection
       */
      @Override
      public Collection<E> makeConfirmedCollection() {
          return new HashSet<>();
      }
  
      /**
       * Returns a full Set for use in modification testing.
       *
       * @return a confirmed full collection
       */
      @Override
      public Collection<E> makeConfirmedFullCollection() {
          final Collection<E> set = makeConfirmedCollection();
          set.addAll(Arrays.asList(getFullElements()));
          return set;
      }
  
      /**
       * Makes a full set by first creating an empty set and then adding
       * all the elements returned by {@link #getFullElements()}.
       *
       * Override if your set does not support the add operation.
       *
       * @return a full set
      */
     @Override
     public Set<E> makeFullCollection() {
         final Set<E> set = makeObject();
         set.addAll(Arrays.asList(getFullElements()));
         return set;
     }
 
     /**
      * Makes an empty set.  The returned set should have no elements.
      *
      * @return an empty set
      */
     @Override
     public abstract Set<E> makeObject();
 
     /**
      * Tests {@link Set#equals(Object)}.
      */
     @Test
     @SuppressWarnings("unchecked")
     public void testSetEquals() {
         resetEmpty();
         assertEquals(getCollection(), getConfirmed(), "Empty sets should be equal");
         verify();
 
         final Collection<E> set2 = makeConfirmedCollection();
         set2.add((E) "foo");
         assertFalse(getCollection().equals(set2), "Empty set shouldn't equal nonempty set");
 
         resetFull();
         assertEquals(getCollection(), getConfirmed(), "Full sets should be equal");
         verify();
 
         set2.clear();
         set2.addAll(Arrays.asList(getOtherElements()));
         assertFalse(getCollection().equals(set2), "Sets with different contents shouldn't be equal");
     }
 
     /**
      * Tests {@link Set#hashCode()}.
      */
     @Test
     public void testSetHashCode() {
         resetEmpty();
         assertEquals(getCollection().hashCode(), getConfirmed().hashCode(),
                 "Empty sets have equal hashCodes");
 
         resetFull();
         assertEquals(getCollection().hashCode(), getConfirmed().hashCode(),
                 "Equal sets have equal hashCodes");
     }
 
     /**
      * Provides additional verifications for sets.
      */
     @Override
     public void verify() {
         super.verify();
 
         assertEquals(getConfirmed(), getCollection(), "Sets should be equal");
         assertEquals(getConfirmed().hashCode(), getCollection().hashCode(),
                      "Sets should have equal hashCodes");
         final Collection<E> set = makeConfirmedCollection();
         for (final E element : getCollection()) {
             assertTrue(set.add(element), "Set.iterator should only return unique elements");
         }
     }
 
 }