def test_get_links_contains_cell_when_linked():
cell_A = Cell(0, 0)
cell_B = Cell(1, 1)
cell_A.link(cell_B)
links = cell_A.links
assert cell_B in links
def test_link_cell_links_cell():
cell_A = Cell(0, 0)
cell_B = Cell(1, 1)
cell_A.link(cell_B)
assert cell_A.is_linked(cell_B)
assert not cell_B.is_linked(cell_A)