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The DSI utilities are a mishmash of classes accumulated during the last twenty years in projects developed at the DSI (Dipartimento di Scienze dell'Informazione, i.e., Information Sciences Department), now DI (Dipartimento di Informatica, i.e., Informatics Department), of the Universita` degli Studi di Milano.

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package it.unimi.dsi;

/*
 * DSI utilities
 *
 * Copyright (C) 2002-2018 Sebastiano Vigna
 *
 *  This library is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU Lesser General Public License as published by the Free
 *  Software Foundation; either version 3 of the License, or (at your option)
 *  any later version.
 *
 *  This library 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 Lesser General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, see .
 *
 */


import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import it.unimi.dsi.fastutil.ints.IntArrayList;
import it.unimi.dsi.fastutil.ints.IntArrays;
import it.unimi.dsi.fastutil.longs.LongBigArrays;
import it.unimi.dsi.util.SplitMix64Random;

import java.util.Collections;

import org.junit.Test;

public class UtilTest {

	@Test
	public void testFormatBinarySize() {
		assertEquals("1", Util.formatBinarySize(1));
		assertEquals("2", Util.formatBinarySize(2));
		boolean ok = false;
		try {
			Util.formatBinarySize(6);
		}
		catch(IllegalArgumentException e) {
			ok = true;
		}
		assertTrue(ok);
		assertEquals("128", Util.formatBinarySize(128));
		assertEquals("1Ki", Util.formatBinarySize(1024));
		assertEquals("2Ki", Util.formatBinarySize(2048));
		assertEquals("1Mi", Util.formatBinarySize(1024 * 1024));
		assertEquals("2Mi", Util.formatBinarySize(2 * 1024 * 1024));
		assertEquals("1Gi", Util.formatBinarySize(1024 * 1024 * 1024));
		assertEquals("2Gi", Util.formatBinarySize(2L * 1024 * 1024 * 1024));
		assertEquals("1Ti", Util.formatBinarySize(1024L * 1024 * 1024 * 1024));
		assertEquals("2Ti", Util.formatBinarySize(2L * 1024 * 1024 * 1024 * 1024));
	}

	@Test
	public void testFormatSize() {
		assertEquals("1", Util.formatSize(1));
		assertEquals("2", Util.formatSize(2));
		assertEquals("128", Util.formatSize(128));
		assertEquals("1.00K", Util.formatSize(1000));
		assertEquals("2.00K", Util.formatSize(2000));
		assertEquals("2.50K", Util.formatSize(2500));
		assertEquals("1.00M", Util.formatSize(1000 * 1000));
		assertEquals("2.00M", Util.formatSize(2 * 1000 * 1000));
		assertEquals("1.00G", Util.formatSize(1000 * 1000 * 1000));
		assertEquals("2.00G", Util.formatSize(2L * 1000 * 1000 * 1000));
		assertEquals("1.00T", Util.formatSize(1000L * 1000 * 1000 * 1000));
		assertEquals("2.00T", Util.formatSize(2L * 1000 * 1000 * 1000 * 1000));
	}


	@Test
	public void testInvertPermutation() {
		for(int k = 10; k-- != 0;) {
			final int[] p = Util.identity(k * 10);
			IntArrays.shuffle(p, new SplitMix64Random(0));
			int[] q = Util.invertPermutation(p);
			q = Util.invertPermutation(q);
			assertArrayEquals(q, p);
		}
	}

	@Test
	public void testInvertPermutationInPlace() {
		assertArrayEquals(new int[] { 0, 1, 2 }, Util.invertPermutationInPlace(new int[] { 0, 1, 2 }));
		assertArrayEquals(new int[] { 1, 0 }, Util.invertPermutationInPlace(new int[] { 1, 0 }));
		assertArrayEquals(new int[] { 0, 2, 1 }, Util.invertPermutationInPlace(new int[] { 0, 2, 1 }));
		assertArrayEquals(new int[] { 3, 0, 1, 2 }, Util.invertPermutationInPlace(new int[] { 1, 2, 3, 0 }));

		for(int k = 10; k-- != 0;) {
			final int[] p = Util.identity(k * 10);
			Collections.shuffle(IntArrayList.wrap(p));
			final int[] q = Util.invertPermutation(p);
			Util.invertPermutationInPlace(p);
			assertArrayEquals(q, p);
		}
	}

	@Test
	public void testInvertBigPermutation() {
		for(int k = 10; k-- != 0;) {
			final long[][] p = Util.identity(k * 10L);
			LongBigArrays.shuffle(p, new SplitMix64Random(0));
			long[][] q = Util.invertPermutation(p);
			q = Util.invertPermutation(q);
			assertArrayEquals(q, p);
		}
	}

	@Test
	public void testBigInvertPermutationInPlace() {
		assertArrayEquals(new long[][] { { 0, 1, 2 } }, Util.invertPermutationInPlace(new long[][] { { 0, 1, 2 } }));
		assertArrayEquals(new long[][] { { 1, 0 } }, Util.invertPermutationInPlace(new long[][] { { 1, 0 } }));
		assertArrayEquals(new long[][] { { 0, 2, 1 } }, Util.invertPermutationInPlace(new long[][] { { 0, 2, 1 } }));
		assertArrayEquals(new long[][] { { 3, 0, 1, 2 } }, Util.invertPermutationInPlace(new long[][] { { 1, 2, 3, 0 } }));

		for(int k = 10; k-- != 0;) {
			final long[][] p = Util.identity(k * 10L);
			LongBigArrays.shuffle(p, new SplitMix64Random(0));
			final long[][] q = Util.invertPermutation(p);
			Util.invertPermutationInPlace(p);
			assertArrayEquals(q, p);
		}
	}
}