minor changes

back/test/mail/saveMessage-test.ts

@@ -146,6 +146,7 @@ describe("saveMessage", () => {
 
             await register.save();
 
+            // the owner of the room will be the recipient (not us)
             expect(createOrRegisterOnExistence).toHaveBeenCalledWith(db.users[1].id, RoomType.DM);
         });
         it("should create a GROUP when there is a new first message from us to multiple recipients", async () => {