https://github.com/rubygems/rubygems/commit/573ffad3ea

Since now every functionality that changes in Bundler 4 is under a
setting, we can enable that setting to test the new functionality,
without having to run our full CI twice.

This can actually be seen as increasing coverage, because Bundler 4
functionality will now be tested on Windows, MacOS, or any other
environment where previously "Bundler 4 mode" was not running.

https://github.com/rubygems/rubygems/commit/1cb3e009fc

https://github.com/rubygems/rubygems/commit/28b6a7cf5e

the overwritten binstub in the test has a final new line that makes it
not match "OMG" exactly from the beginning, that's why the test passes,
but `bintubs` command without `--force` flag is not supposed to update
the binstub.

This change fixes the test to test what's supposed to update the
binstub, and also fixes the assertion that that it will fail in the
future if `--force` stops updating the binstub.

https://github.com/rubygems/rubygems/commit/dfc9023337

https://github.com/rubygems/rubygems/commit/bb66253f2c

This is in preparation for deprecating source-less gemfiles.

https://github.com/rubygems/rubygems/commit/d6493fa3e2

Since our helpers now raise by default if the subcommand fails, these
will never actually fail and are not necessary.

https://github.com/rubygems/rubygems/commit/6153b9321e

Using File.open without a block leaves a file reference that causes issues with file operations

commands/binstubs_spec.rb
install/gems/compact_index_spec.rb
install/gems/dependency_api_spec.rb
install/gems/standalone_spec.rb
runtime/executable_spec.rb

https://github.com/rubygems/rubygems/commit/4b9a6ca156