Add tests for instance store module

• Tester le module store de l'instance

added Improvment label

assigned to @tguillas

added Doing label

created merge request !8 (merged) to address this issue

mentioned in merge request !8 (merged)

mentioned in commit 6a890695

closed with merge request !8 (merged)

mentioned in merge request !11 (merged)

mentioned in commit 60df09f5

removed Doing label