public void TestCanPlace()
{
Grid g = new Grid(9,0);
g.Place(3,1,1);
for (int i = 0; i < 9; i++)
{
Assert.AreEqual(false, g.CanPlace(3, i, 1)); //test row
Assert.AreEqual(false, g.CanPlace(3, 1, i)); //test col
}
for (int i = 0; i < 3; i++)
for (int j = 0; j < 3; j++ )
Assert.AreEqual(false, g.CanPlace(3, i, j)); //test row
Assert.AreEqual(true, g.CanPlace(3, 5, 5)); //test col
}