You want shop. test on localhost during the day, then the real client domain pointed at staging, then maybe the same domain pointed at a new server before DNS moves. You do not need dnsmasq for that.
Source: [Dev.to](https://dev.to/locahl_9bd77121e3d366f72f/how-to-switch-local-and-staging-domains-with-the-hosts-file-4aj7)