Use: certbot renew --dry-run
Optionally add --cert-name X if just testing one certificate (see: certbot certificates)
--force-renewal forces Certbot to perform renewal even if the cert is not due (by age or ARI). But, successful challenges are retained by Let's Encrypt and the manual auth hooks are only used when a fresh challenge is needed. The --dry-run option deactivates prior challenges.
Note --dry-run will not get a fresh cert but will not disturb any prior cert even if using --test-cert for the prior one.
See the profiles page for the "Authorization reuse period" that applies to eachprofile: Profiles - Let's Encrypt. The default profile reuses challenges for 30 days
Update: I think we covered this back in May 
Certonly --force-renewal - #2 by MikeMcQ