Add unit tests to chemkinTest

[mliu49]

I started out trying to write tests for each untested line, but I realized that it wasn't really helping. A major untested part was writing chemkin files, so I added some additional checks to existing tests. The end result was only +6% coverage within chemkin.py. To increase coverage more, we need to test reading and writing the other kinetics formats besides Arrhenius and Chebyshev.

[mention-bot]

@mliu49, thanks for your PR! By analyzing the history of the files in this pull request, we identified @nickvandewiele, @connie and @jwallen to be potential reviewers.

[KEHANG]

@mliu49 not sure what mock is doing here. Can you explain why we need add it as a new RMG dependency? or how you recommend using it in the future?

[mliu49]

mock enables creation of fake instances of python modules. In this case, mock is used to create a fake logging module to intercept calls to logging.warning. This allows unit testing that specific logging statements are actually created.

In this case, the unit tests I added aren't particularly important, but I had written them in my initial attempt to cover line-by-line. I quickly realized that that wasn't a particularly good way to go about it, but I kept the tests anyway.

If you don't think those tests are worth keeping, then I'm fine with not adding them. However, I think mock does have future value in unit testing.

Edit: FYI, mock was converted to a standard module in python 3.

[rwest]

I like it. But perhaps add a few docstrings or comments in the unit test to help others understand what on earth is going on? To someone who's not worked with mock before, it's not particularly obvious. And it might be something we want to replicate elsewhere.

[mliu49]

I will add more info about mock to the docstrings.

[KEHANG]

@mliu49 ready to merge?