Sorting chcolatey Pacakges On version

PackageSorter.cs

using System;
using System.Collections.Generic;

namespace OrderPackages
{
    public class PackagesSorter:IComparer<string>
    {
        private static readonly char LevelSeperator = ".".ToCharArray()[0];
        private const string PreRelease = "-pre";

        public int Compare(string x, string y)
        {
            var xsplits = x.Split(LevelSeperator).GetUpperBound(0);
            var ysplits = y.Split(LevelSeperator).GetUpperBound(0);
            if (x.Contains(PreRelease)) x = x.Substring(0, x.Length - PreRelease.Length);
            if (y.Contains(PreRelease)) y = y.Substring(0, y.Length - PreRelease.Length);
            var maxsplits = ysplits > xsplits? xsplits: ysplits;
            if (! String.IsNullOrEmpty(x))
            {
                for (var i = 1; i <= maxsplits; i++)
                {
                    if (Int32.Parse(x.Split(LevelSeperator)[i]) >
                        Int32.Parse(y.Split(LevelSeperator)[i])) return 1;
                    if (Int32.Parse(x.Split(LevelSeperator)[i]) <
                        Int32.Parse(y.Split(LevelSeperator)[i])) return -1;
                }
                if (ysplits > xsplits) return - 1;
                return ysplits < xsplits ? 1 : 0;
            }
            else
            {
                if (!String.IsNullOrEmpty(y))
                {
                    return - 1;
                }
                else
                {
                    return 0;
                }
            }
        }
    }
}

Tests.cs

using System;
using System.Collections.Generic;
using NUnit.Framework;

namespace OrderPackages
{
    public class PackagesSorterTests
    {
        [Test]
        public void ShouldOrderPackagesWithOnly1NumberCorrectly()
        {
            var packages = new List<String>() {"Choco.0.1.5", "Choco.0.1.4", "Choco.0.1.6", "Choco.0.1.1"};
            packages.Sort(new PackagesSorter());
            Assert.AreEqual("Choco.0.1.1", packages[0]);
            Assert.AreEqual("Choco.0.1.4", packages[1]);
            Assert.AreEqual("Choco.0.1.5", packages[2]);
            Assert.AreEqual("Choco.0.1.6", packages[3]);
        }

        [Test]
        public void ShouldOrderPackagesWithOnlyWhereTwoPackagesHaveTheSameNumber()
        {
            var packages = new List<String>() { "Choco.0.1.5", "Choco.0.1.5", "Choco.0.1.6", "Choco.0.1.1" };
            packages.Sort(new PackagesSorter());
            Assert.AreEqual("Choco.0.1.1", packages[0]);
            Assert.AreEqual("Choco.0.1.5", packages[1]);
            Assert.AreEqual("Choco.0.1.5", packages[2]);
            Assert.AreEqual("Choco.0.1.6", packages[3]);
        }

        [Test]
        public void ShouldOrderPackagesWithOnly1NumberCorrectlyWhereOneIsPre()
        {
            var packages = new List<String>() { "Choco.0.1.5", "Choco.0.1.4-pre", "Choco.0.1.6", "Choco.0.1.1" };
            packages.Sort(new PackagesSorter());
            Assert.AreEqual("Choco.0.1.1", packages[0]);
            Assert.AreEqual("Choco.0.1.4-pre", packages[1]);
            Assert.AreEqual("Choco.0.1.5", packages[2]);
            Assert.AreEqual("Choco.0.1.6", packages[3]);
        }

        [Test]
        public void ShouldOrderPackagesWhere1EndsInDoubleDigitsNumberCorrectly()
        {
            var packages = new List<String>() { "Choco.0.1.5", "Choco.0.1.14", "Choco.0.1.6", "Choco.0.1.1" };
            packages.Sort(new PackagesSorter());
            Assert.AreEqual("Choco.0.1.1", packages[0]);
            Assert.AreEqual("Choco.0.1.5", packages[1]);
            Assert.AreEqual("Choco.0.1.6", packages[2]);
            Assert.AreEqual("Choco.0.1.14", packages[3]);
        }

        [Test]
        public void ShouldOrderPackagesWhereAllEndInDoubleDigitsNumberCorrectly()
        {
            var packages = new List<String>() { "Choco.0.1.15", "Choco.0.1.14", "Choco.0.1.26", "Choco.0.1.31" };
            packages.Sort(new PackagesSorter());
            Assert.AreEqual("Choco.0.1.14", packages[0]);
            Assert.AreEqual("Choco.0.1.15", packages[1]);
            Assert.AreEqual("Choco.0.1.26", packages[2]);
            Assert.AreEqual("Choco.0.1.31", packages[3]);
        }

        [Test]
        public void ShouldOrderPackagesWhere1HasAMiddleNumberInDoubleDigitsNumberCorrectly()
        {
            var packages = new List<String>() { "Choco.0.1.5", "Choco.0.11.4", "Choco.0.1.6", "Choco.0.1.1" };
            packages.Sort(new PackagesSorter());
            Assert.AreEqual("Choco.0.1.1", packages[0]);
            Assert.AreEqual("Choco.0.1.5", packages[1]);
            Assert.AreEqual("Choco.0.1.6", packages[2]);
            Assert.AreEqual("Choco.0.11.4", packages[3]);
        }

        [Test]
        public void ShouldOrderPackagesWhere1HasAFirstNumberInDoubleDigitsNumberCorrectly()
        {
            var packages = new List<String>() { "Choco.0.1.5", "Choco.10.1.4", "Choco.0.1.6", "Choco.0.1.1" };
            packages.Sort(new PackagesSorter());
            Assert.AreEqual("Choco.0.1.1", packages[0]);
            Assert.AreEqual("Choco.0.1.5", packages[1]);
            Assert.AreEqual("Choco.0.1.6", packages[2]);
            Assert.AreEqual("Choco.10.1.4", packages[3]);
        }

        [Test]
        public void ShouldOrderPackagesWhere1HasAllNumbersInDoubleDigitsNumberCorrectly()
        {
            var packages = new List<String>() { "Choco.0.1.5", "Choco.10.11.14", "Choco.0.1.6", "Choco.0.1.1" };
            packages.Sort(new PackagesSorter());
            Assert.AreEqual("Choco.0.1.1", packages[0]);
            Assert.AreEqual("Choco.0.1.5", packages[1]);
            Assert.AreEqual("Choco.0.1.6", packages[2]);
            Assert.AreEqual("Choco.10.11.14", packages[3]);
        }

        [Test]
        public void ShouldOrderPackagesWhenOneIsEmpty()
        {
            var packages = new List<String>() { "Choco.0.1.5", "", "Choco.0.1.6", "Choco.0.1.1" };
            packages.Sort(new PackagesSorter());
            Assert.AreEqual("", packages[0]);
            Assert.AreEqual("Choco.0.1.1", packages[1]);
            Assert.AreEqual("Choco.0.1.5", packages[2]);
            Assert.AreEqual("Choco.0.1.6", packages[3]);
        }

        [Test]
        public void ShouldOrderPackagesWhenTwoAreEmpty()
        {
            var packages = new List<String>() { "Choco.0.1.5", "", "", "Choco.0.1.1" };
            packages.Sort(new PackagesSorter());
            Assert.AreEqual("", packages[0]);
            Assert.AreEqual("", packages[1]);
            Assert.AreEqual("Choco.0.1.1", packages[2]);
            Assert.AreEqual("Choco.0.1.5", packages[3]);
        }
        
    }
}