private static void checkAllPixels(HfzFile file, int expectedCount)
        {
            int count = 0;
            for (uint i = 1; i <= file.header.nx; i++)
            {
                for (uint j = 1; j <= file.header.ny; j++)
                {
                    file.getPixelAt(i, j);
                    count++;
                }
            }

            Assert.AreEqual(expectedCount, count);
        }