Bug 25189: Unit tests

Bug 25189: Unit tests

Adds new test for not adding authority if some already exist

Also replaces use of 'SearchAuthorities' as it is Zebra specific

Signed-off-by: Andrew Fuerste-Henry <andrew@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit 258d0b0ecd6450fea09677f0607efdedb33cc16c)

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
(cherry picked from commit 6a395eab2d3ce6c9564b387eaa8f863632518997)
Signed-off-by: Victor Grousset/tuxayo <victor@tuxayo.net>