class Arc_Tests(unittest.TestCase):
def setUp(self):
self.constraints = Arcs(8)
self.variables = Variables(8)
def test_there_are_two_arcs_for_each_constraint(self):
self.assertEqual(112, len(self.constraints.set))
def test_constraints_can_detect_two_queens_in_the_same_diagonal(self):
self.variables.queens[0].value = 4
self.variables.queens[3].value = 7
self.assertEqual(False, self.constraints.verify(self.variables))
def test_constraints_can_detect_two_queens_in_the_opposing_diagonals(self):
self.variables.queens[4].value = 6
self.variables.queens[7].value = 3
self.assertEqual(False, self.constraints.verify(self.variables))
def test_constraints_can_detect_three_queens_in_the_same_diagonal(self):
self.variables.queens[0].value = 4
self.variables.queens[2].value = 6
self.variables.queens[3].value = 7
self.assertEqual(False, self.constraints.verify(self.variables))
def test_constraints_can_detect_two_queens_in_the_same_rows(self):
self.variables.queens[0].value = 1
self.variables.queens[7].value = 1
self.assertEqual(False, self.constraints.verify(self.variables))
def test_constraints_can_detect_three_queens_in_the_same_rows(self):
self.variables.queens[0].value = 4
self.variables.queens[1].value = 4
self.variables.queens[2].value = 4
self.assertEqual(False, self.constraints.verify(self.variables))
def test_constraints_will_allow_unassigned_values_to_pass_constraints(
self):
self.variables.queens[0].value = 1
self.variables.queens[1].value = 3
self.assertEqual(True, self.constraints.verify(self.variables))
def test_contraints_will_prune_domains(self):
self.variables.queens[0].value = 1
self.constraints.wipeout(self.variables, self.variables.queens[0])
self.variables.queens[1].value = 3
self.constraints.wipeout(self.variables, self.variables.queens[1])
self.assertEqual(set([5, 6, 7, 8]), self.variables.queens[2].domain)
self.assertEqual(set([2, 6, 7, 8]), self.variables.queens[3].domain)
self.assertEqual(set([2, 4, 7, 8]), self.variables.queens[4].domain)
self.assertEqual(set([2, 4, 5, 6, 7]), self.variables.queens[7].domain)
def test_contraints_will_return_nothing_when_assigned_values_wipeout_a_domain(
self):
self.variables.queens[0].value = 2
self.constraints.wipeout(self.variables, self.variables.queens[0])
self.variables.queens[1].value = 4
self.constraints.wipeout(self.variables, self.variables.queens[1])
self.variables.queens[2].value = 1
self.constraints.wipeout(self.variables, self.variables.queens[2])
self.variables.queens[3].value = 3
self.constraints.wipeout(self.variables, self.variables.queens[3])
self.variables.queens[4].value = 5
self.assertEqual(
None,
self.constraints.wipeout(self.variables, self.variables.queens[4]))
def test_constraints_will_return_the_pruned_values(self):
self.variables.queens[0].value = 1
values = self.constraints.wipeout(self.variables,
self.variables.queens[0])
self.assertItemsEqual([(3, 1), (2, 3), (7, 8), (2, 1), (7, 1), (5, 6),
(4, 1), (4, 5), (5, 1), (1, 2), (3, 4), (6, 1),
(1, 1), (6, 7)], values)
def test_constraints_can_restore_domains(self):
self.variables.queens[0].value = 1
values = self.constraints.wipeout(self.variables,
self.variables.queens[0])
self.constraints.restore(self.variables, values)
self.assertEqual(set([1, 2, 3, 4, 5, 6, 7, 8]),
self.variables.queens[0].domain)
self.assertEqual(set([1, 2, 3, 4, 5, 6, 7, 8]),
self.variables.queens[1].domain)
self.assertEqual(set([1, 2, 3, 4, 5, 6, 7, 8]),
self.variables.queens[7].domain)
