Classify - Fix dsl tests

[lucasrcezimbra]

Related to #333

[yaythomas]

awesome, thank you so much!

[yaythomas]

also thanks for adding test_from_step_definition - it's currently failing because, I suspect, we don't have a custom __eq__ override on the dsl classes. When I cache objects, I generally declare the classes with __slots__ and with an eq like this:

    def __eq__(self, other):
        """Equality comparison checks Pipeline and info objects are equal."""
        type_self = type(self)

        if type_self is type(other):
            all_slots = [p for c in type_self.__mro__ for p in getattr(
                c, '__slots__', [])]
            return all(
                getattr(self, s, id(self)) == getattr(other, s, id(other))
                for s in all_slots)
        else:
            return False

I'll get on it shortly!