Suggested improvements in regard to PhpUnit tests

I ran into this repo while trying to found out what common patterns for Wercker configuration files are with PHP.

As there is an ongoing effort to improve the quality of all/any resources about PHP (there is still a lot of prejudice against the language based on its legacy), I fell obliged to make an effort to offer some education in the form of best practices when using PHP and PhpUnit (like adding docblocks, annotations, configuration and directories separating code).

These suggestion are not necessarily meant for the education of you (the repository owner) as much as they are for the public at large that might stumble across this code and not know any better. 

I also took the liberty of adding a few more tests to get to 100% coverage.

On a side-note, it has been good fun taking Wercker for a spin. I feel inclined to recommend Wercker over other services (like the more hyped Travis, for instance) to my peers.