public void TestHorizontal1D()
{
double[] data = {
1.0, 2.0, 3.0
};
Image image = new Image(3, data);
IntegralImage integral_image = new IntegralImage(image);
Assert.AreEqual(1.0, integral_image[0][0]);
Assert.AreEqual(3.0, integral_image[0][1]);
Assert.AreEqual(6.0, integral_image[0][2]);
}