def test_simple_iter_clauses(self):
"""Test basic expression iter_clauses functionality."""
# ensure defaults to CNF
b = BooleanExpression('A or B or C or D')
self.assertTrue(b.is_cnf)
self.assertTrue(b.is_dnf)
clauses = b.iter_clauses()
self.assertEqual(
repr(next(clauses)),
'<BooleanExpression "A or B or C or D">')
with self.assertRaises(StopIteration):
next(clauses)
# ensure falls back to DNF
b = BooleanExpression('(A and B and C) or (D and E and F)')
self.assertFalse(b.is_cnf)
self.assertTrue(b.is_dnf)
clauses = b.iter_clauses()
self.assertEqual(
repr(next(clauses)),
'<BooleanExpression "A and B and C">')
self.assertEqual(
repr(next(clauses)),
'<BooleanExpression "D and E and F">')
with self.assertRaises(StopIteration):
next(clauses)
def test_iter_clauses_not_normal_form(self):
"""Test attempting iter_clauses when not in normal form."""
b = BooleanExpression('A nand B')
self.assertFalse(b.is_cnf)
self.assertFalse(b.is_dnf)
with self.assertRaises(RequiresNormalFormError):
for clause in b.iter_clauses():
pass