Implement Unit Test

[kefniark]

A module like this one, used in so many project recently, should be at least partially cover by unit test.

I took a look, some part can be easily tested :

• EventEmitter
• Logger
• Tomes

But some other like the mageClient (the more important one) has a bit too much part mixed together to write nice tests.
A refactoring will probably be needed for that to happen.