def test_ac3_change_solvable_multi_step():
constraints = {("B", "A"): (lambda x, y: x < y),
("A", "B"): (lambda y, x: x < y),
("C", "B"): (lambda x, y: x != y),
("B", "C"): (lambda y, x: x != y)}
variables = {"A": {1, 2, 3}, "B": {2, 3}, "C": {2, 3}}
assert ac3.ac3(constraints, variables, ac3.get_all_arcs(constraints))
assert {"A": {3}, "B": {2}, "C": {3}} == variables
def backtrack(variables, constraints):
ac3.ac3(constraints, variables, ac3.get_all_arcs(constraints))
cp = ConstraintProblem(variables, constraints)
return _backtrack(cp)
def test_get_all_arcs_one_binary():
constraints = {("SA", "WA"): (lambda x, y: x != y)}
assert [("SA", "WA")] == ac3.get_all_arcs(constraints)
def test_ac3_unsolvable():
constraints = {("A", "B"): (lambda x, y: x == y)}
variables = {"A": {1, 2, 3}, "B": {42}}
assert not ac3.ac3(constraints, variables, ac3.get_all_arcs(constraints))
def test_ac3_change_solvable():
constraints = {("A", "B"): (lambda x, y: x != y)}
variables = {"A": {1, 2, 3}, "B": {2}}
assert ac3.ac3(constraints, variables, ac3.get_all_arcs(constraints))
assert {"A": {1, 3}, "B": {2}} == variables
def test_ac3_no_changes():
constraints = {("A", "B"): (lambda x, y: x > y)}
variables = {"A": {3, 4, 5}, "B": {1}}
assert ac3.ac3(constraints, variables, ac3.get_all_arcs(constraints))
assert {"A": {3, 4, 5}, "B": {1}} == variables
def test_get_all_arcs_no_binary():
constraints = {("SA",): (lambda x: x != "42"),
("WA",): (lambda x: x > 123)}
assert [] == ac3.get_all_arcs(constraints)
def test_get_all_arcs_mixed():
constraints = {("SA", "WA"): (lambda x: x != "wuff"),
("WA",): (lambda x: x > 123),
("DBC", "EFG"): (lambda x: x > 123)}
assert [("SA", "WA"), ("DBC", "EFG")] == ac3.get_all_arcs(constraints)