See https://github.com/choderalab/Repex/
This repository contains a suite of molecular systems that can be used for the testing of various molecular mechanics related software. The idea is that this repository will host a number classes that generate OpenMM objects for simulating the desired systems.
These classes will also contain the member functions that calculate known analytical properties of these systems, enabling the proper testing.
Note: setup.py does not currently work. Also, the doctests must be run from the testsystems directory. This will be fixed.