gistfile1.rb

# To run this code:
#
#   gem install rspec
#   rspec code.rb
#
require 'rspec'
 
User = Struct.new(:github_handle, :followers)
 
class Github # External dependency
  def self.fetch_followers(*)
    %w(alex marcin marek)
  end
end
 
# Client code
 
class SomeClientCode
  def update_followers_for(user)
    gh = GithubFollowers.new(user)
    unless gh.any?
      gh.fetch!
      gh.update
    end
  end
end
 
class GithubFollowers
  @@followers = []
 
  attr_reader :user
  
  def self.followers
    @@followers
  end
 
  def initialize(user)
    @user = user
  end
 
  def fetch!
    @@followers = Github.fetch_followers(user.github_handle)
  end
 
  def any?
    @@followers.any?
  end
 
  def update
    followers = []
    user.followers = []
    @@followers.each do |follower|
      user.followers << follower
      followers << follower
    end
    followers
  end
end
 
RSpec.describe GithubFollowers do
  let(:user) { User.new('hans', []) }
  let(:subject) { described_class.new(user) }
 
  it 'fetches the github followers' do
    allow(Github).to receive(:fetch_followers) { %w(john james finn) }
    subject.fetch!
    expect(subject.update).to eq(%W(john james finn))
    expect(user.followers).to eq(%w(john james finn))
  end
end