ok: session A starts with 0 drafts
ok: first upsert inserts
ok: list returns the new draft
ok: payload persisted correctly
ok: second upsert updates same row
ok: still 1 draft after update
ok: qty updated to 3
ok: session A list doesn't leak session B drafts
ok: session B has its own draft
ok: delete with wrong session id rejected
ok: draft still in session A after rejected delete
ok: correct delete succeeds
ok: session A back to 0 drafts
DONE