They are hard to maintain (and even read) in their current state.
It's an entangled boil of inherited classes whose perimeter is conflated
together (initialize svn repository, initialize loader with a given state,
etc...).
It's complicated to the point of adding a new scenario about multiple visits
loading scenario is not a simple task [1].
It'd be nice to disentangle this and also aligns with what other loaders are
now using, pytest fixtures!
[1] D3307