Write unit tests to improve coverage

[ghost]

Right now, the reported coverage on the badge in readme is 31%. Let's get it to 100%!

[ghost]

PRs are welcome! If you'd like to contribute, this is an easy way to get started :)

[wusyong]

Wrote a few tests and run them a bit, I realized there are way too many branch conditions need to cover. Maybe we should disable branch info? What we want to make sure is line and function coverage are good enough. Trying to satisfy them all is not practical imho.

[ghost]

@wusyong That sounds reasonable - I think covering all branches is a bar too high.

[tshepang]

Another way to look at it is for 31% not be seen as bad, as in there is no need to get to 100%. That is, it's good to know that some branches are not covered. Does the service make it easy to see non-branch coverage results?

[wusyong]

@tshepang I think you are right. It just confused me when I added a test but the rate becomes lower because of more branch misses. Configure this should be easy anyway. I guess this comes down to what's the goal for the code coverage rate we are going to show (line/branch/path).

[ghost]

Unit tests have moved into the smaller subcrates. See #188