Autotest.add_hook :initialize do |at|
  at.clear_mappings

  at.add_mapping %r%/^lib/(.*)\.rb$% do |_, m|
    possible = File.basename(m[1])
    files_matching %r%^spec/.*(#{possible}_spec)\.rb$%
  end

  at.add_mapping(%r%^spec/.*\_spec.rb$%) {|filename, _| filename }
end