Tests are missing or outdated

[Jonarzz]

Tests should be added and/or updated to match the code as they are well outdated.

The tests would help to keep the code managable, would encourage refactoring (which is needed as well) and would make the code more understandable for others.

Run configuration as described in the Travis CI configuration file.

[MePsyDuck]

I can try to update tests to improve code coverage as well as try to refactor them.

[Jonarzz]

That would be great! Totally go for it and thanks in advance!