Performance Test for: array, list and dictionary

PerformanceTest

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;

namespace WorkPlace
{
    class Program
    {
        private const int _collectionSize = 1000000;

        static void Main(string[] args)
        {
            Stopwatch stopwatch = new Stopwatch();
            Random random = new Random();
            int index = random.Next(1, _collectionSize);

            Console.WriteLine("All collections are type of `int`");
            Console.WriteLine("Maximum collection size: {0}", _collectionSize);
            Console.WriteLine("Random generated index used for value lookup: {0}\n", index);

            #region array

            stopwatch.Start();
            var array = ArrayTest();
            stopwatch.Stop();

            Console.WriteLine("Array populating time elapsed: {0}", stopwatch.Elapsed);

            stopwatch.Restart();

            int lookupValue = array[index];

            stopwatch.Stop();

            Console.WriteLine("Array lookup time elapsed: {0}", stopwatch.Elapsed);
            Console.WriteLine("Size: {0} bytes", GetObjectSize(array));

            #endregion

            Console.WriteLine("==============");

            #region list

            stopwatch.Restart();
            var list = ListTest();
            stopwatch.Stop();

            Console.WriteLine("List populating time elapsed: {0}", stopwatch.Elapsed);

            stopwatch.Restart();

            lookupValue = list[index];

            stopwatch.Stop();

            Console.WriteLine("List lookup time elapsed: {0}", stopwatch.Elapsed);
            Console.WriteLine("Size: {0} bytes", GetObjectSize(list));

            #endregion

            Console.WriteLine("==============");

            #region dictionary

            stopwatch.Restart();
            var dictionary = DictionaryTest();
            stopwatch.Stop();

            Console.WriteLine("Dictionary populating time elapsed: {0}", stopwatch.Elapsed);

            stopwatch.Restart();

            lookupValue = dictionary[index];

            stopwatch.Stop();

            Console.WriteLine("Dictionary lookup time elapsed: {0}", stopwatch.Elapsed);
            Console.WriteLine("Size: {0} bytes", GetObjectSize(dictionary));

            #endregion
        }

        static int GetObjectSize(object obj)
        {
            BinaryFormatter binaryFormatter = new BinaryFormatter();
            MemoryStream memoryStream = new MemoryStream();
            byte[] array;

            binaryFormatter.Serialize(memoryStream, obj);
            array = memoryStream.ToArray();

            return array.Length;
        }

        static int[] ArrayTest()
        {
            var array = new int[_collectionSize];

            for (int i = 0; i < _collectionSize; i++)
            {
                array[i] = i;
            }

            return array;
        }

        static List<int> ListTest()
        {
            var list = new List<int>();

            for (int i = 0; i < _collectionSize; i++)
            {
                list.Add(i);
            }

            return list;
        }

        static Dictionary<int, int> DictionaryTest()
        {
            var dictionary = new Dictionary<int, int>();

            for (int i = 0; i < _collectionSize; i++)
            {
                dictionary.Add(i, i);
            }

            return dictionary;
        }
    }
}