Add unit tests for "authentication error" in Trojitá
completed by: Toby Chen
mentors: Jan Kundrát (jkt), paalsteek
A recent change https://gerrit.vesnicky.cesnet.cz/r/198 in Trojitá (done within this GCI, btw) added a newly visible property to an important class. Your jobs is to make sure that this property is being maintained correctly and to add unit tests checking just that.