thiagoa

# app/models/twitter_client_factory.rb
class TwitterClientFactory
  def call(params)
    Twitter::REST::Client.new do |config|
      config.consumer_key = params['consumer_key']
      config.consumer_secret = params['consumer_secret']
      config.access_token = params['access_token']
      config.access_token_secret = params['access_token_secret']
    end
  end

thiagoa

context 'when config is not passed' do
  before do
    @consumer_key_backup = ENV['TWITTER_CONSUMER_KEY']
    @consumer_secret_backup = ENV['TWITTER_CONSUMER_SECRET']
    @access_token_backup = ENV['TWITTER_ACCESS_TOKEN']
    @access_token_secret_backup = ENV['TWITTER_ACCESS_TOKEN_SECRET']

    ENV['TWITTER_CONSUMER_KEY'] = 'ck'
    ENV['TWITTER_CONSUMER_SECRET'] = 'cs'
    ENV['TWITTER_ACCESS_TOKEN'] = 'at'

thiagoa

# app/models/twitter_client_factory.rb
class TwitterClientFactory
  def call(params = {})
    params = default_params.merge(params)

    Twitter::REST::Client.new do |config|
      config.consumer_key = params['consumer_key']
      config.consumer_secret = params['consumer_secret']
      config.access_token = params['access_token']
      config.access_token_secret = params['access_token_secret']

thiagoa

# spec/models/twitter_timeline_hub_spec.rb
require 'spec_helper'
require 'twitter'
require_relative '../../app/models/twitter_timeline_hub'

RSpec.describe TwitterTimelineHub do
  describe '#call' do
    it 'collaborates with twitter_client to get a timeline and delivers a result struct' do
      twitter_client = instance_double(Twitter::REST::Client)
      allow(twitter_client).to receive(:user_timeline).and_return([])

thiagoa

class TwitterTimelineHub
  Result = Struct.new(:status, :tweets)

  def initialize(twitter_client)
    @twitter_client = twitter_client
  end

  def call(user, count: 20)
    tweets = @twitter_client.user_timeline(user, count: count)
    Result.new(:ok, tweets)

thiagoa

def build_tweet_double(user_name:, mention_name:, text:, created_at:)
  user = instance_double(Twitter::User, screen_name: user_name)
  mention = instance_double(
    Twitter::Entity::UserMention,
    screen_name: mention_name
  )
  instance_double(
    Twitter::Tweet,
    user: user,
    text: text,

thiagoa

context 'when the timeline is found' do
  it 'returns a result object with tweets and an ok status' do
    twitter_client = instance_double(Twitter::REST::Client)
    tweet = build_tweet_double(
      user_name: 'thiagoaraujos',
      text: 'Foo @bar',
      mention_name: 'bar',
      created_at: Date.new(2016, 1, 1)
    )
    allow(twitter_client).to receive(:user_timeline).and_return([tweet])

thiagoa

class TwitterTimelineHub
  Result = Struct.new(:status, :tweets)

  def initialize(twitter_client = TwitterClientFactory.new.call)
    @twitter_client = twitter_client
  end

  def call(user, count: 20)
    tweets = @twitter_client.user_timeline(user, count: count).map do |tweet|
      { created_at: tweet.created_at,

thiagoa

class TwitterTimelineHub
  Result = Struct.new(:status, :tweets)

  def initialize(twitter_client)
    @twitter_client = twitter_client
  end

  def call(user, count: 20)
    tweets = fetch_user_timeline(user, count: count)
    Result.new(:ok, tweets)

thiagoa

context 'when the timeline is not found' do
  it 'returns a result with no tweets and not_found status' do
    twitter_client = instance_double(Twitter::REST::Client)
    allow(twitter_client).to receive(:user_timeline)
      .with('screen_name', count: 5)
      .once { fail Twitter::Error::NotFound }

    twitter_hub = TwitterTimelineHub.new(twitter_client)
    result = twitter_hub.call('screen_name', count: 5)