Add test to attest that duplicate choices are forbidden
Add test to attest that duplicate choices are forbidden

uclouvain/osis,uclouvain/OSIS-Louvain,uclouvain/osis_louvain,uclouvain/osis_louvain,uclouvain/osis_louvain,uclouvain/osis,uclouvain/osis,uclouvain/OSIS-Louvain,uclouvain/osis,uclouvain/OSIS-Louvain