namespace AioNet.LinqTest;

using AioNet.Linq;

public class ExtendedLinqTest
{
    [Fact]
    public void FindOneCombinationFor3Elements_SubsequenceLength3()
    {
        var foundCombinations = new[] { 1, 2, 3 }.Combinations(3);
        Assert.Single(foundCombinations);

        var onlyCombination = foundCombinations.First();
        Assert.Contains(1, onlyCombination);
        Assert.Contains(2, onlyCombination);
        Assert.Contains(3, onlyCombination);
    }

    [Fact]
    public void FindThreeCombinationsFor3Elements_SubsequenceLength2()
    {
        var foundCombinations = new[] { 1, 2, 3 }.Combinations(2);
        Assert.Equal(3, foundCombinations.Count());
    }

    [Theory]
    [InlineData(1)]
    [InlineData(2)]
    [InlineData(3)]
    [InlineData(4)]
    [InlineData(5)]
    public void EachSubsequenceIsCorrectLength(int subsequenceLength)
    {
        var foundCombinations = new[] { 1, 2, 3, 4, 5, 6 }.Combinations(subsequenceLength);

        foreach (var foundCombination in foundCombinations)
        {
            Assert.Equal(subsequenceLength, foundCombination.Count());
        }
    }
}