eval_gemfile is not supported by appraisal.

Error:

appraisal-2.2.0/lib/appraisal/gemfile.rb:30:in `run':
undefined method `eval_gemfile' for #<Appraisal::Gemfile:0x000055dfb5f5bb18> (NoMethodError)

eval_gemfile is useful for sharing dependencies between multiple Gemfiles.

E.g. I have a rubocop.gemfile that's included into the main Gemfile but also into a separate rubocop-only Gemfile for running as a separate task on CI.