public void SumTest2()
{
Bitmap image = Properties.Resources.image2;
int expected = 0;
for (int i = 3; i < 9; i++)
for (int j = 2; j < 10; j++)
expected += image.GetPixel(i, j).R;
int actual = (int)Tools.Sum(image, new Rectangle(3, 2, 9 - 3, 10 - 2));
Assert.AreEqual(expected, actual);
}