def test_implementation_of_cut_edges_matches_naive_method():
graph = three_by_three_grid()
assignment = {0: 1, 1: 1, 2: 2, 3: 1, 4: 1, 5: 2, 6: 2, 7: 2, 8: 2}
updaters = {'cut_edges': cut_edges}
partition = Partition(graph, assignment, updaters)
flip = {4: 2}
new_partition = Partition(parent=partition, flips=flip)
result = cut_edges(new_partition)
naive_cut_edges = {edge for edge in graph.edges
if new_partition.crosses_parts(edge)}
assert edge_set_equal(result, naive_cut_edges)
def test_cut_edges_by_part_gives_same_total_edges_as_naive_method():
graph = three_by_three_grid()
assignment = {0: 1, 1: 1, 2: 2, 3: 1, 4: 1, 5: 2, 6: 2, 7: 2, 8: 2}
updaters = {'cut_edges_by_part': cut_edges_by_part}
partition = Partition(graph, assignment, updaters)
# 112 111
# 112 -> 121
# 222 222
flip = {4: 2, 2: 1, 5: 1}
new_partition = Partition(parent=partition, flips=flip)
result = new_partition['cut_edges_by_part']
naive_cut_edges = {tuple(sorted(edge)) for edge in graph.edges
if new_partition.crosses_parts(edge)}
assert naive_cut_edges == {tuple(sorted(edge)) for part in result for edge in result[part]}
def test_cut_edges_can_handle_multiple_flips():
graph = three_by_three_grid()
assignment = {0: 1, 1: 1, 2: 2, 3: 1, 4: 1, 5: 2, 6: 2, 7: 2, 8: 2}
updaters = {'cut_edges': cut_edges}
partition = Partition(graph, assignment, updaters)
# 112 111
# 112 -> 121
# 222 222
flip = {4: 2, 2: 1, 5: 1}
new_partition = Partition(parent=partition, flips=flip)
result = new_partition['cut_edges']
naive_cut_edges = {tuple(sorted(edge)) for edge in graph.edges
if new_partition.crosses_parts(edge)}
assert result == naive_cut_edges
