def test_apply_predicate(self):
predicate = grammar.Predicate(True)
Y = grammar.TypeExpression('Y')
X = grammar.TypeExpression('X', fields=(Y, ))
result = X._apply_predicate_(predicate)
self.assertIsInstance(result, grammar.TypeExpression)
self.assertEqual(result.fields, (Y, ))
def test_hashable(self):
a = grammar.TypeExpression('X')
b = grammar.TypeExpression('Y', fields=(a, ))
c = grammar.TypeExpression('Y', fields=(a, ))
d = grammar.TypeExpression('Z', predicate=grammar.Predicate("stuff"))
self.assertIsInstance(a, collections.Hashable)
# There really shouldn't be a collision between these:
self.assertNotEqual(hash(a), hash(d))
self.assertEqual(b, c)
self.assertEqual(hash(b), hash(c))
def test_mod_w_none_predicate(self):
X = grammar.TypeExpression('X', predicate=None)
predicate = grammar.Predicate("Truthy")
self.assertIs((X % predicate).predicate, predicate)
def test_mod_w_existing_predicate(self):
X = grammar.TypeExpression('X', predicate=grammar.Predicate('Truthy'))
with self.assertRaisesRegex(TypeError, 'predicate'):
X % grammar.Predicate('Other')
def test_validate_predicate_w_valid(self):
predicate = grammar.Predicate(True)
X = grammar.TypeExpression('X')
X._validate_predicate_(predicate)
