experimental_build_stubbed_independent_replacement.rb

# frozen_string_literal: true

def experimental_spec(file, occurrence)
  parts = file.split('/')
  dir = parts[0..-2]
  filename = "experiment_#{occurrence}_#{__FILE__.split('.').first}_#{parts[-1]}"
  File.join(*dir, filename)
end

def experiment(file, expression, replacement, index = nil)
  new_content = Fast.replace_file file, expression, ->(node, _) do
    if index.nil?
      experiment(file, expression, replacement, match_index)
    elsif match_index == index
      instance_exec(node, &replacement)
    end
  end
  if new_content
    File.open(experimental_spec(file, index), 'w+') { |f| f.puts new_content }
    [index, new_content]
  end
end