def test_is_null_throws_error_on_not_null_value():
"""
Tests that the `is_null()` method throws an ArgumentNullError
when it is supplied with a type that is not None (Null).
"""
# Arrange
type = TypeExample()
validator = ObjectValidator(type, 'type')
# Assert
with pytest.raises(ArgumentNullError):
# Act
validator.is_null()
def test_is_null_accepts_null_value():
"""
Tests that the `is_null()` method does not throw an ArgumentNullError
when it is supplied with a type that is None (Null).
"""
# Arrange
type = None
validator = ObjectValidator(type, 'type')
# Act
try:
validator.is_null()
# Assert
except ArgumentNullError:
pytest.fail(f'The object should have been None (Null), but an error occurred.')
def test_is_null_returns_validator_self():
"""
Tests if the `is_true()` validator method returns itself after the validation is performed,
so that additional validations can be performed.
"""
# Arrange
type = None
validator = ObjectValidator(type, 'type')
# Act
validator_returned = validator.is_null()
# Assert
assert validator_returned is validator