You can use the add_development_dependency
in the gemspec
file. You'll still have to require
it in your lib/something.rb
file within a begin .. rescue LoadError
block. (Edit 2, see below)
In your case, it will be something like the following:
spec.add_development_dependency 'pry', '~> 0.9.12.2'
The purpose of add_development_dependency
is to separate the gems into dependencies that get installed when you execute gem install mygem
vs development-only dependencies that are installed only when you execute gem install mygem --development
.
Edit: @Pierre-Louis Gottfrois' solution
Modify the Gemfile
directly and add a test
group. This question describes the process. This does not appear to be a preferred solution according to Yehuda Katz.
Edit 2: begin require ... rescue LoadError
is apparently a common practice for Ruby scripts, according to this Making Ruby Gems article.