Unit and integration tests are lacking

[thesketh]

At present, the unit tests mostly cover the charmm_containers module. This is intentional - these classes have been the source of most of the issues I've discovered in the past - but issues with Molecule and Structure would also have far-reaching implications. The unit tests should be expanded upon.

Additionally, more integration tests are required. The OpenMM test is useful, as it tests both structure generation and PSF/PDB format structure. More tests using OpenMM or other simulation packages, perhaps for some more difficult molecules, would be ideal.

[thesketh]

Additional tests added in 3c9c8e2, so now over 80% coverage.

Tests to cover command line usage are still necessary.

[RMeli]

Any short-term plans to bump code coverage even higher?

[thesketh]

I've added tests for the command-line portion of the software, so coverage is ~91% now