public void ApplyGrayscale()
{
var oldR = LargeBitmap.GetPixel(0, 0).R;
var oldG = LargeBitmap.GetPixel(0, 0).G;
var oldB = LargeBitmap.GetPixel(0, 0).B;
int intensity = (oldR + oldG + oldB) / 3;
int newR = intensity;
int newG = intensity;
int newB = intensity;
ImageHandler.ApplyGrayscale(LargeBitmap);
Assert.AreEqual(newR, LargeBitmap.GetPixel(0, 0).R);
Assert.AreEqual(newG, LargeBitmap.GetPixel(0, 0).G);
Assert.AreEqual(newB, LargeBitmap.GetPixel(0, 0).B);
}