Unit test assertions are not effective

[rzvoncek]

I'm having troubles confirming the unit tests actually work.

In #10, I added a test. Because of having trouble with this locally already, I initially pushed a commit that should fail the CI buit it didn't.

So I pushed another commit with a different assertion method, which made the CI fail as expected. I then pushed one more to make the CI green.

I'm not familiar with org.assertj.core.api.Assertions, so there's a chance I'm just missing a switch somewhere to make them effective. At any case, I'd like to know how to run the unit tests properly.