How to test puts in rspec

I think the best way is to use rspec build in output matcher https://www.relishapp.com/rspec/rspec-expectations/docs/built-in-matchers/output-matcher

Fore example,
this is your class

class MakeIt
  def awesome(text)
    puts "Awesome #{text}"
  end
end

and your test

describe MakeIt do
  describe '#awesome' do
    it 'prints awesome things' do
      expect do
        MakeIt.new.awesome('tests')
      end.to output('Awesome tests').to_stdout
    end

    it 'does not print not awesome things' do
      expect do
        MakeIt.new.awesome('tests')
      end.to_not output('Not awesome tests').to_stdout
    end
  end
end

Nice, clean and by the book!