gistfile1.cs

using System;
using System.Diagnostics;
using System.Threading;

using Indigo.ForTesting;

using Machine.Specifications;

namespace Indigo.Tools.Tests
{
	[Subject(typeof(Memoize))]
	public class When_a_function_is_memoized
	{
		static Func<int, int> Func;
		static int FirstResult;
		static int SecondResult;
		static Stopwatch FirstTime;
		static Stopwatch SecondTime;

		Establish context = () =>
			{
				Func = x =>
					{
						Thread.Sleep(1000);
						return x * 10;
					};

				Func = Memoize.This(Func);
			};

		Because of = () =>
			{
				FirstTime = Measure.Time(() => FirstResult = Func(9));
				SecondTime = Measure.Time(() => SecondResult = Func(9));
			};

		It should_compute_the_correct_result = () => FirstResult.ShouldEqual(90);
		It should_take_a_long_time_on_the_first_invocation = () => FirstTime.Elapsed.ShouldBeGreaterThan(TimeSpan.FromMilliseconds(900));

		It should_compute_the_correct_result_on_the_second_invocation = () => SecondResult.ShouldEqual(90);
		It should_take_a_short_time_on_the_second_invocation = () => SecondTime.Elapsed.ShouldBeLessThan(TimeSpan.FromMilliseconds(500));
	}
}