Fix/gh333

Fix issue #333 

Basically, logger tests used logger directly as a class. So, caller stack was small and `caller(2)` was enough to gather the relevant information.

When using the method from the DSL the stack is bigger (calls App, calls others.. call logger).
Trying the console logger resulted in `caller(6)`.

Need to test with other loggers.

Meanwhile, updated tests to not verify the source file issue the message. If there is a better approach let me know (like faking the caller).