MAINT: add `--test` flag to converter test
MAINT: add `--test` flag to converter test

bmockler/MOSFiT,mnicholl/MOSFiT,guillochon/FriendlyFit,guillochon/MOSFiT,mnicholl/MOSFiT,villrv/MOSFiT,guillochon/MOSFiT,mnicholl/MOSFiT,bmockler/MOSFiT,villrv/MOSFiT,guillochon/MOSFiT