You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: cli_spec.rb
    path of file: ./repos/opal/spec/lib
    
    the code of the file until where you have to start completion: require 'lib/spec_helper'
require 'opal/cli'
require 'stringio'
require 'tmpdir'

RSpec.describe Opal::CLI do
  let(:file)    { File.expand_path('../fixtures/opal_file.rb', __FILE__) }
  let(:option
    
  def output_and_result_of
    fake_stdout = StringIO.new
    stdout = described_class.stdout
    described_class.stdout = fake_stdout
    result = yield
    output = fake_stdout.tap(&:rewind).read
    return output, result
  ensure
    described_class.stdout = stdout
  end