Hey again ! :) is there a way to test correctly our smart contract, better than doigt manual transactions ?

Hey, yes you can use mando test check https://docs.elrond.com/developers/mandos-reference/overview/

Yes with mandos ? https://docs.elrond.com/developers/mandos-reference/overview/ And if you prefer something more on the actual chain and how you would interact with it. https://docs.elrond.com/sdk-and-tools/erdjs/writing-and-testing-erdjs-interactions/