Add tests that check the line numbers

[Thomasdezeeuw]

We currently don't have any.

[DIvkov575]

Im pretty new to contributing, but I would love to contribute to this repo. Would this be a good issue to start with?

[Thomasdezeeuw]

Im pretty new to contributing, but I would love to contribute to this repo. Would this be a good issue to start with?

Hey @DIvkov575 sorry for the delayed response, I've been traveling.

I think it will be a good first issue. I think the easiest way to get started is to look at tests/filters.rsfor inspiration. If you have a any questions or you get stuck somewhere feel free to ask!