public void AsReadOnly()
{
Assert.IsFalse(grid.IsReadOnly);
Assert.IsTrue(readOnly.IsReadOnly);
Assert.AreSame(readOnly, grid.AsReadOnly());
Assert.AreSame(readOnly, readOnly.AsReadOnly());
}
public void SetUp()
{
grid = new PolygonGrid(element);
readOnly = grid.AsReadOnly();
}