TestHuffmanAllocator.java

package org.itadaki.bzip2;

import static org.junit.Assert.*;

import java.io.IOException;
import java.lang.reflect.Constructor;
import java.util.Arrays;

import org.itadaki.bzip2.HuffmanAllocator;
import org.junit.Test;

/**
 * Tests HuffmanAllocator
 */
public class TestHuffmanAllocator {

    /**
     * Fibonacci sequence
     */
    private static int[] fibonacci = { 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28657, 46368,
	    75025, 121393, 196418, 317811, 514229, 832040, 1346269, 2178309, 3524578, 5702887, 9227465, 14930352 };

    /**
     * @throws IOException
     */
    @Test
    public void testShort1() throws IOException {

	int[] expectedLengths = new int[] { 1 };
	int[] frequencies = new int[] { 1 };
	HuffmanAllocator.allocateHuffmanCodeLengths(frequencies, 32);

	assertArrayEquals(expectedLengths, frequencies);

    }

    /**
     * @throws IOException
     */
    @Test
    public void testShort2() throws IOException {

	int[] expectedLengths = new int[] { 1, 1 };
	int[] frequencies = new int[] { 1, 1 };
	HuffmanAllocator.allocateHuffmanCodeLengths(frequencies, 32);

	assertArrayEquals(expectedLengths, frequencies);

    }

    /**
     * @throws IOException
     */
    @Test
    public void testRegular1() throws IOException {

	int[] expectedLengths = new int[] { 3, 3, 2, 2, 2 };
	int[] frequencies = new int[] { 1, 1, 1, 1, 1 };
	HuffmanAllocator.allocateHuffmanCodeLengths(frequencies, 32);

	assertArrayEquals(expectedLengths, frequencies);

    }

    /**
     * @throws IOException
     */
    @Test
    public void testBoundary1() throws IOException {

	int[] expectedLengths = new int[] { 3, 3, 3, 3, 2, 2 };
	int[] frequencies = new int[] { 0, 0, 1, 1, 1, 1 };
	HuffmanAllocator.allocateHuffmanCodeLengths(frequencies, 3);

	assertArrayEquals(expectedLengths, frequencies);

    }

    /**
     * @throws IOException
     */
    @Test
    public void testFibonacci1() throws IOException {

	int[] expectedLengths = new int[] { 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 19, 19, 18, 17, 16, 16, 14, 13, 12, 11, 10, 9, 8,
		7, 6, 5, 4, 3, 2, 1 };
	int[] frequencies = Arrays.copyOf(fibonacci, 36);
	HuffmanAllocator.allocateHuffmanCodeLengths(frequencies, 20);

	assertArrayEquals(expectedLengths, frequencies);

    }

    /**
     * @throws IOException
     */
    @Test
    public void testFibonacci2() throws IOException {

	int[] expectedLengths = new int[] { 20, 20, 19, 19, 19, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, };
	int[] frequencies = Arrays.copyOf(fibonacci, 22);
	HuffmanAllocator.allocateHuffmanCodeLengths(frequencies, 20);

	assertArrayEquals(expectedLengths, frequencies);

    }

    /**
     * @throws IOException
     */
    @Test
    public void testFibonacci3() throws IOException {

	int[] expectedLengths = new int[] { 20, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, };
	int[] frequencies = Arrays.copyOf(fibonacci, 21);
	HuffmanAllocator.allocateHuffmanCodeLengths(frequencies, 20);

	assertArrayEquals(expectedLengths, frequencies);

    }

    /**
     * @throws IOException
     */
    @Test
    public void testFibonacci4() throws IOException {

	int[] expectedLengths = new int[] { 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 5, 5, 5, 4, 3, 2 };
	int[] frequencies = Arrays.copyOf(fibonacci, 36);
	HuffmanAllocator.allocateHuffmanCodeLengths(frequencies, 6);

	assertArrayEquals(expectedLengths, frequencies);

    }

    /**
     * Pointless test to bump coverage to 100%
     * 
     * @throws Exception
     */
    @Test
    public void testPointlessConstructorTestCoverage() throws Exception {

	Constructor<?> c[] = HuffmanAllocator.class.getDeclaredConstructors();

	c[0].setAccessible(true);
	c[0].newInstance((Object[]) null);

    }

}