Yet another post object wrapping 02

Some testing later a slightly revised post object wrapper.

A tested code base

I've spent some time covering the code base with tests and am more confident the code is beyond a draft phase.
It's code I've written and used before but I wanted to have a common and solid base not to write similar code anymore.
The repository part of it is in early stages and I will try to expand on it to allow for something mimicking the functions of the Laravel Eloquent ORM.
The idea to be able to write code like

$cars = Cars_Repository::all();

or, again abstracting from the technology layer and moving into the domain layer,

$cars = Cars_Repository::where('color', '=', 'red');

PHP 5.3+ alternative

While doing some research to find out alternatives I've found out this package; I like it was it not made for a version of PHP above WordPress minimum requirements.
I would like something I can require in PHP 5.2 compatible plugin and that's not the case.

Next

I will develop the repository class more and implement the functions I can think of.