solve non null constraint in test
solve non null constraint in test

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