ruby 在RSpec中测试STDOUT 3

Posted 2021-05-16

* [ruby - rspec commandline variable input - Stack Overflow](https://www.relishapp.com/rspec/rspec-expectations/v/3-1/docs/built-in-matchers/output-matcher)
* [rspec3で標準入力と標準出力のテスト - memo-mode](http://ganmacs.hatenablog.com/entry/2014/07/26/231607)
* [`output` matcher - Built in matchers - RSpec Expectations - RSpec - Relish](https://www.relishapp.com/rspec/rspec-expectations/v/3-1/docs/built-in-matchers/output-matcher)

class Mirror
  def echo
    puts 'enter something: '
    response = gets.chomp
    puts "#{response}"
  end
end

# ------------------------

require 'rspec'

describe Mirror do
  let(:solver) { described_class.new }

  before do
    # Set fixed input
    allow(ARGF).to receive(:gets) { "phrase\n" }
  end

  describe 'mirror#echo' do
    it { expect { solver.echo }.to output(/phrase/).to_stdout }
  end
end