Add tests for metamodel module

• Tester le module metamodel

added Improvment label

assigned to @tguillas

added Doing label

created merge request !27 (merged) to address this issue

mentioned in merge request !27 (merged)

mentioned in commit 05206d95

closed with merge request !27 (merged)

mentioned in merge request !30 (merged)

mentioned in commit 0a6a906d

removed Doing label