HuffmanCompressorTests.cs

using Algorithms.DataCompression;
using Algorithms.Sorters.Comparison;
using FluentAssertions;
using NUnit.Framework;
using NUnit.Framework.Internal;

namespace Algorithms.Tests.Compressors;

public static class HuffmanCompressorTests
{
    [TestCase("This is a string", "101010110111011101110111100011111010010010010011000")]
    [TestCase("Hello", "1101110010")]
    [TestCase("dddddddddd", "1111111111")]
    [TestCase("a", "1")]
    [TestCase("", "")]
    public static void CompressingPhrase(string uncompressedText, string expectedCompressedText)
    {
        //Arrange
        var sorter = new BubbleSorter<HuffmanCompressor.ListNode>();
        var translator = new Translator();
        var huffman = new HuffmanCompressor(sorter, translator);

        //Act
        var (compressedText, decompressionKeys) = huffman.Compress(uncompressedText);
        var decompressedText = translator.Translate(compressedText, decompressionKeys);

        //Assert
        Assert.That(compressedText, Is.EqualTo(expectedCompressedText));
        Assert.That(decompressedText, Is.EqualTo(uncompressedText));
    }

    [Test]
    public static void DecompressedTextTheSameAsOriginal(
        [Random(0, 1000, 100, Distinct = true)]
        int length)
    {
        //Arrange
        var sorter = new BubbleSorter<HuffmanCompressor.ListNode>();
        var translator = new Translator();
        var huffman = new HuffmanCompressor(sorter, translator);
        var text = Randomizer.CreateRandomizer().GetString(length);

        //Act
        var (compressedText, decompressionKeys) = huffman.Compress(text);
        var decompressedText = translator.Translate(compressedText, decompressionKeys);

        //Assert
        Assert.That(decompressedText, Is.EqualTo(text));
    }

    [Test]
    public static void ListNodeComparer_NullIsUnordered()
    {
        var comparer = new HuffmanCompressor.ListNodeComparer();
        var node = new HuffmanCompressor.ListNode('a', 0.1);

        comparer.Compare(node, null).Should().Be(0);
        comparer.Compare(null, node).Should().Be(0);
        comparer.Compare(null, null).Should().Be(0);
    }
}