MovingAverageTests.cs

using System.Linq;
using NUnit.Framework;

namespace yield
{
	[TestFixture]
	public class MovingAverageTests
	{
		[Test]
		public void SmoothEmptySequence()
		{
			CheckAverage(10, new double[] { }, new double[] { });
		}

		[Test]
		public void SmoothSingleZero()
		{
			CheckAverage(10, new[] { 0.0 }, new[] { 0.0 });
		}

		[Test]
		public void SmoothSingleNonZeroValue()
		{
			CheckAverage(10, new[] { 100.0 }, new[] { 100.0 });
		}

		[Test]
		public void SmoothTwoValues()
		{
			CheckAverage(2, new[] { 0, 20.0 }, new[] { 0, 10.0 });
		}

		[Test]
		public void SmoothTwoValues2()
		{
			CheckAverage(2, new[] { 10, 0.0 }, new[] { 10, 5.0 });
		}

		[Test]
		public void SmoothTwoValuesWithSmallWindow()
		{
			CheckAverage(1, new[] { 10, 0.0 }, new[] { 10, 0.0 });
		}

		[Test]
		public void SmoothWithWindow2()
		{
			CheckAverage(2, new double[] { 1, 2, 3, 4, 5, 6 }, new double[] { 1, 1.5, 2.5, 3.5, 4.5, 5.5 });
		}

		[Test]
		public void SmoothWithWindow3()
		{
			CheckAverage(3, new double[] { 3, 3, 3, 6, 6, 6 }, new double[] { 3, 3, 3, 4, 5, 6 });
		}

		[Test]
		public void SmoothWithLargeWindow()
		{
			CheckAverage(100500, new double[] { 1, 2, 3, 4, 5, 6 }, new double[] { 1, 1.5, 2, 2.5, 3, 3.5 });
		}

		private void CheckAverage(int windowWidth, double[] ys, double[] expectedYs)
		{
			var dataPoints = ys.Select((v, index) => new DataPoint(GetX(index), v));
			var actual = Factory.CreateAnalyzer().MovingAverage(dataPoints, windowWidth).ToList();
			Assert.AreEqual(ys.Length, actual.Count);
			for (var i = 0; i < actual.Count; i++)
			{
				Assert.AreEqual(GetX(i), actual[i].X, 1e-7);
				Assert.AreEqual(ys[i], actual[i].OriginalY, 1e-7);
				Assert.AreEqual(expectedYs[i], actual[i].AvgSmoothedY, 1e-7);
			}
		}

		private double GetX(int index)
		{
			return (index - 3.0) / 2;
		}
	}
}