/*
 * Copyright (C) 2008 The Guava Authors
 *
 * 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.google.common.collect.testing.testers;

import static com.google.common.collect.testing.features.CollectionFeature.ALLOWS_NULL_VALUES;

import com.google.common.collect.testing.MinimalSet;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

/**
 * Tests {@link List#equals}.
 *
 * <p>This class is GWT compatible.
 *
 * @author George van den Driessche
 */
public class ListEqualsTester<E> extends AbstractListTester<E> {
  public void testEquals_otherListWithSameElements() {
    assertTrue(
        "A List should equal any other List containing the same elements.",
        getList().equals(new ArrayList<E>(getSampleElements())));
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  public void testEquals_otherListWithDifferentElements() {
    ArrayList<E> other = new ArrayList<E>(getSampleElements());
    other.set(other.size() / 2, getSubjectGenerator().samples().e3);
    assertFalse(
        "A List should not equal another List containing different elements.",
        getList().equals(other));
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  public void testEquals_otherListContainingNull() {
    List<E> other = new ArrayList<E>(getSampleElements());
    other.set(other.size() / 2, null);
    assertFalse("Two Lists should not be equal if exactly one of them has "
        + "null at a given index.",
        getList().equals(other));
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  public void testEquals_containingNull() {
    ArrayList<E> elements = new ArrayList<E>(getSampleElements());
    elements.set(elements.size() / 2, null);
    collection = getSubjectGenerator().create(elements.toArray());
    List<E> other = new ArrayList<E>(getSampleElements());
    assertFalse("Two Lists should not be equal if exactly one of them has "
        + "null at a given index.",
        getList().equals(other));
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  public void testEquals_shorterList() {
    Collection<E> fewerElements = getSampleElements(getNumElements() - 1);
    assertFalse("Lists of different sizes should not be equal.",
        getList().equals(new ArrayList<E>(fewerElements)));
  }

  public void testEquals_longerList() {
    Collection<E> moreElements = getSampleElements(getNumElements() + 1);
    assertFalse("Lists of different sizes should not be equal.",
        getList().equals(new ArrayList<E>(moreElements)));
  }

  public void testEquals_set() {
    assertFalse("A List should never equal a Set.",
        getList().equals(MinimalSet.from(getList())));
  }
}