day of week kata

gistfile1.txt

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

namespace dayofweekkata
{
    public class PrettyPrinter
    {
        public static string Convert(params int[] integers)
        {
            var ordered = integers.OrderBy(x=>x).ToList();

            var groups = new List<List<int>>();
            var currentGrouping = new List<int>();

            foreach(var integer in ordered)
            {
                if (currentGrouping.Count == 0)
                {
                    currentGrouping.Add(integer);
                    continue;
                }

                var previous = currentGrouping.Last();
                if (integer - previous == 1) 
                {
                    currentGrouping.Add(integer);
                    continue;
                }

                groups.Add(currentGrouping);
                currentGrouping = new List<int> {integer};
            }

            if (currentGrouping.Any())
            {
                groups.Add(currentGrouping);
            }

            var strings = new List<string>();
            foreach (var stack in groups)
            {
                if (stack.Count < 3)
                {
                    var asDays = stack.Select(x => (DayOfWeek)x);
                    strings.Add(string.Join(", ", asDays));
                }
                else
                {
                     strings.Add((DayOfWeek)stack.First() + "-" + (DayOfWeek)stack.Last());
                }
            }

            return string.Join(", ", strings);
        }
    }

    public enum DayOfWeek
    {
        Mon = 1,
        Tue,
        Wed,
        Thu,
        Fri,
        Sat,
        Sun
    }
    
    [TestFixture]
    public class PrettyPrinterTests
    {
        [TestCase(1, "Mon")]
        [TestCase(2, "Tue")]
        [TestCase(3, "Wed")]
        [TestCase(4, "Thu")]
        [TestCase(5, "Fri")]
        [TestCase(6, "Sat")]
        [TestCase(7, "Sun")]
        public void Convert_SingleDayProvided_ConvertsToAppropriateValue(int dayId, string dayShort)
        {
            var output = PrettyPrinter.Convert(dayId);

            Assert.That(output, Is.EqualTo(dayShort));
        }

        [Test]
        public void Convert_TwoSequentialDays_Joins()
        {
            var output = PrettyPrinter.Convert(1, 2);

            Assert.That(output, Is.EqualTo("Mon, Tue"));            
        }

        [Test]
        public void Convert_TwoSequentialDaysProvidedBackwards_Joins()
        {
            var output = PrettyPrinter.Convert(2, 1);

            Assert.That(output, Is.EqualTo("Mon, Tue"));            
        }

        [Test]
        public void Convert_ThreeSequentialDays_Hyphenates()
        {
            var output = PrettyPrinter.Convert(1, 2, 3);

            Assert.That(output, Is.EqualTo("Mon-Wed"));            
        }

        [Test]
        public void Convert_ThreeSequentialDaysPlusWeekend_Hyphenates()
        {
            var output = PrettyPrinter.Convert(1, 2, 3, 6, 7);

            Assert.That(output, Is.EqualTo("Mon-Wed, Sat, Sun"));
        }

        [Test]
        public void Convert_ThreeSequentialDaysFromTheMiddlePlusWeekend_Hyphenates()
        {
            var output = PrettyPrinter.Convert(2, 3, 4, 6, 7);

            Assert.That(output, Is.EqualTo("Tue-Thu, Sat, Sun"));
        }
    }

    /*   1,2,3,4,5,6,7:  Mon-Sun
    1,2,3,6,7:      Mon-Wed, Sat, Sun
    1,3,4,5,6:      Mon, Wed-Sat
    2,3,4,6,7:      Tue-Thu, Sat, Sun
    1,3,4,6,7:      Mon, Wed, Thu, Sat, Sun
    7:              Sun
    1,7:            Mon, Sun
    1,8:            ArgumentError*/
}