Bug 21849: Add unit tests

Bug 21849: Add unit tests

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
(cherry picked from commit 2dbaaa300877ff6d96ae84b5a703753d97b6c340)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
(cherry picked from commit aa565b8e9919ee414d0693f391b141985ebacb93)

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
(cherry picked from commit 0a6c0c32604ebbd89ccff8d2dc0ff4a11bd204dd)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>