def test_iter_dnf_clauses_not_dnf(self):
"""Test attempting iter_dnf_clauses when not in DNF."""
b = BooleanExpression('(A or B) and (C or D)')
self.assertFalse(b.is_dnf)
with self.assertRaises(RequiresNormalFormError):
for clause in b.iter_dnf_clauses():
pass
def test_simple_iter_dnf(self):
"""Test basic expression iter_dnf_clauses functionality."""
b = BooleanExpression('(A and B) or (C and D) or (E and F)')
self.assertTrue(b.is_dnf)
self.assertFalse(b.is_cnf)
clauses = b.iter_dnf_clauses()
self.assertEqual(
repr(next(clauses)),
'<BooleanExpression "A and B">')
self.assertEqual(
repr(next(clauses)),
'<BooleanExpression "C and D">')
self.assertEqual(
repr(next(clauses)),
'<BooleanExpression "E and F">')
with self.assertRaises(StopIteration):
next(clauses)