QWERTYkez.Mensura/QWERTYkez.Mensura.Tests/CollectionsPow2ExtensionsTest.cs

namespace QWERTYkez.Mensura.Tests;

public class CollectionsPow2ExtensionsTest
{
    [Fact]
    public void Pow2_Array_CalculatesCorrectly()
    {
        // Arrange
        Length[] source = [new(2), new(3), new(10)];

        // Act
        Length[] result = source.Pow2<Length, Length>();

        // Assert
        Assert.Equal(4, result[0]._Value);
        Assert.Equal(9, result[1]._Value);
        Assert.Equal(100, result[2]._Value);
    }

    [Fact]
    public void Pow2_NullableArray_HandlesNulls()
    {
        // Arrange
        Length?[] source = [new(5), null, new(4)];

        // Act
        Length?[] result = source.Pow2<Length, Length>();

        // Assert
        Assert.Equal(25, result[0]?._Value);
        Assert.Null(result[1]);
        Assert.Equal(16, result[2]?._Value);
    }

    [Fact]
    public void Pow2_List_ReturnsCorrectResult()
    {
        // Arrange
        var source = new List<Length> { new(2), new(8) };

        // Act
        var result = source.Pow2<Length, Length>();

        // Assert
        Assert.Equal(4, result[0]._Value);
        Assert.Equal(64, result[1]._Value);
    }

    [Fact]
    public void Pow2_IEnumerable_ProcessesCorrectly()
    {
        // Arrange
        IEnumerable<Length> source = new HashSet<Length> { new(3), new(7) };

        // Act
        var result = source.Pow2<Length, Length>().ToList();

        // Assert
        Assert.Contains(result, x => x._Value == 9);
        Assert.Contains(result, x => x._Value == 49);
    }

    [Fact]
    public void Pow2_DestinationTooShort_ThrowsArgumentException()
    {
        // Arrange
        Length[] source = [new(2), new(3)];
        Length[] dest = new Length[1];

        // Act & Assert
        Assert.Throws<ArgumentException>(() => source.Pow2(dest));
    }
}