Implement and Test in One File with bundler/inline and rspec/autorun
Sometimes I want to create a tiny one-off script that intended to run on a sandbox environment like a Docker container and needs only one file. Most of the time, I also need test frameworks to do some refactoring. It can be done with bundler/inline and rspec/autorun.
require 'bundler/inline' gemfile do source 'https://rubygems.org' gem 'rspec' end def doit 'return a string' end require 'rspec/autorun' RSpec.describe '#doit' do example do expect(doit).to be_a(String) end end Usually, Bundler reads the dependencies from Gemfile.