https://www.ruby-lang.org/en/news/2025/12/25/ruby-4-0-0-released/
We need to add `ostruct` as a dev dependency because it doesn't come
as a default gem with Ruby 4.0 anymore.
Lock minitest < 6 since v6 has some incompatibilities with released
versions of Rails that will be fixed in future versions.
This is something I didn't run into a few other gems, but SimpleForm
did, presumabily because it touches additional areas like AV tests.
Devise hasn't been tested with Mongoid since Rails version 5, only 4.x was still running those tests.
This enables the tests again on all currently supported Rails versions, with their respective mongoid supported versions. There were a couple of minor tweaks to make it happen, namely:
* The way we were dropping the session before doesn't work in later versions so I changed back to calling `purge!` which appears to work fine. We used to call `Mongoid.purge!` but that changed in #4686.
* Some of the configs in the Rails test app were setting Active Record values when outside of the AR ORM tests, updated those to make sure they are not set when running mongoid ORM tests.
* The validations added to the shared admin code in tests were only checking for Rails version 5.1, but we need to use the same check for AR 5.1 that is used in code, otherwise it will try to use methods not available in mongoid there.
We pointed to github to fix issues with Ruby 2.7 and kwargs, but since
then a version 1.0.5 was released which includes those fixes.
There's a few more things in their main, but nothing we need if all is
green.
