How do you get this to not output 'foo' ?

gistfile1.rb

class Foo
  attr_reader :number

  def initialize
    puts 'foo'
    @number = 1
  end
end

describe Foo do
  describe '#new' do
    it 'sets number' do
      foo = Foo.new
      expect(foo.number).to eql 1
    end
  end
end