Test giving invalid entries to the log processor as if the gonx library did not work properly

[Ullaakut]

In order to properly test the entry parser, we need to make sure that even if a future version of gonx (the parsing library) happens to be sending us invalid data, we handle the errors correctly.

This can be easily done by writing tests that do not use gonx but simply programmatically instantiate gonx.Entry objects and fill them manually with erroneous data.

However, since this is tedious and that I own the version of the library that I use, I know that these tests are most likely not needed for an MVP so I will tag this as a potential future improvement.