Today 2 PRs were merged that enable testing Ruby 2.7 on Smart Proxy and Hammer (and plugins). This is posted just for awareness. Foreman (and plugins) will follow soon.
https://github.com/theforeman/foreman-infra/commit/45b1f6563e0881db6d764325f995977797a81f3f
https://github.com/theforeman/foreman-infra/commit/4e86950a489662eac2ad74b5ad5efec51006b018
Thanks @mmoll!