/*

 * Copyright (c) 2011 Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/* @test

 * @summary Test MergeSort

 *

 * @library ../../../src/sample/share/forkjoin/mergesort

 * @build MergeSortTest MergeDemo MergeSort

 * @run main MergeSortTest

 */

import java.util.Arrays;

import java.util.Random;

public class MergeSortTest {

    private Random random;

    private MergeSort target;

    public MergeSortTest(Random random, MergeSort target) {

        this.random = random;

        this.target = target;

    }

    public static void main(String[] args) {

        MergeSortTest test = new MergeSortTest(new Random(), new MergeSort(Runtime.getRuntime().availableProcessors() * 4));

        test.run();

    }

    private int[] generateArray(int elements) {

        int[] array = new int[elements];

        for (int i = 0; i < array.length; ++i) {

            array[i] = random.nextInt(10);

        }

        return array;

    }

    private void run() {

        testSort();

        testSortSingle();

        testSortEmpty();

        testLong();

    }

    public void testLong() {

        for (int i = 0; i < 1000; ++i) {

            int elements = 1 + i * 100;

            int[] array = generateArray(elements);

            int[] copy = Arrays.copyOf(array, array.length);

            Arrays.sort(copy);

            target.sort(array);

            assertEqual(copy, array);

        }

   }

    private void testSortEmpty() {

        int[] array = { };

        target.sort(array);

        assertEqual(new int[] { }, array);

    }

    private void testSortSingle() {

        int[] array = { 1 };

        target.sort(array);

        assertEqual(new int[] { 1 }, array);

    }

    private void testSort() {

        int[] array = { 7, 3, 9, 0, -6, 12, 54, 3, -6, 88, 1412};

        target.sort(array);

        assertEqual(new int[] { -6, -6, 0, 3, 3, 7, 9, 12, 54, 88, 1412 }, array);

    }

    private void assertEqual(int[] expected, int[] array) {

        if (!Arrays.equals(expected, array)) {

            throw new RuntimeException("Invalid sorted array!");

        }

    }

}