require "rspec/autorun" すると ruby で spec が実行できる

これまた知らんかった。へー。

で exe/rspec 見るとこう。

#!/usr/bin/env ruby

begin
  require 'rspec/autorun'
rescue LoadError
  $stderr.puts <<-EOS
#{'*'*50}
  Could not find 'rspec/autorun'

  This may happen if you're using rubygems as your package manager, but it is not
  being required through some mechanism before executing the rspec command.

  You may need to do one of the following in your shell:

    # for bash/zsh
    export RUBYOPT=rubygems

    # for csh, etc.
    set RUBYOPT=rubygems

  For background, please see http://gist.github.com/54177.
#{'*'*50}
  EOS
  exit(1)
end

require "rspec/autorun" してるだけだったという。。。