public void GetCellFromPoint()
{
WorldGrid grid = new WorldGrid(10000, 10000, 1000, 1000);
Assert.Equal(
new Tuple <int, int>(6, 1),
grid.GetCellFromPoint(new Point(5200, 120))
);
Assert.Equal(
new Tuple <int, int>(1, 1),
grid.GetCellFromPoint(new Point(100, 100))
);
Assert.Throws <ArgumentOutOfRangeException>(
() => grid.GetCellFromPoint(new Point(-200, 200))
);
}