def test_is_type_of__raises__with_type_error():
    """
    When invalid type is given to is_type_of,
    should raise ValidationError
    """
    settings = Dynaconf(
        validators=[Validator("ENV_FOR_DYNACONF", is_type_of="invalid")]
    )

    with pytest.raises(ValidationError):
        settings.validators.validate()

    When invalid type is given to is_type_of,
    should raise ValidationError
    
tests/test_validators.py