Write a test suite

[Libbum]

This hasn't been done at all yet, but is required.

• main.rs
• config.rs
• input.rs
• output.rs
• grid.rs
• potential.rs

[Libbum]

7b284a3 links codecov, so we can see how we're doing with this.

[Libbum]

There have been a few issues with coverage rankings that are now fixed. We have a low coverage amount mainly because all of my functions pass in config et al. which are quite bulky to build for a test. I wonder what the best method of fixing that is?

Also, many things I do are large computations or file io, which I need to read up on how to build tests for these things. For the moment, without coverage here there's going to be little use of the testing suite.

[Libbum]

The git version of tarpaulin now supports codecov. So we can update to that soon.

[Libbum]

There's an issue in the compiler that is making tarpaulin fail when trying to compile serde_derive with -no-pie. Monitoring the status, but this is out of my league to fix right now, so will park this move.

[Libbum]

Check tarpaulin now, there have been a number of version bumps since last looking into this. Nothing on the open issue, but it may be resolved through other means...

Edit: nope. The author is attempting to patch the rust core. Seems deep.

[Libbum]

The current code coverage map has some pretty heavy issues, so don't trust it too much.