Add UserSegments#user_segment_emails helper method

Why:

Both Newsletters and Email Downloads need the same logic: To extract the
emails from all the users in the segment that have newsletter flag
active, removing all empty email values.

How:

1- UserSegments#user_segment_emails holds that repeated logic and is used
on both Newsletter & EmailDownload.

2- Rename Newsletter#list_of_recipients to list_of_recipient_emails as
it is more descriptive. There is no need to pass entire Users around,
only the emails are needed at Mailer#newsletter method.

3- Cleanup Newsletter#list_of_recipient_emails model spec scenario

app/controllers/admin/emails_download_controller.rb

@@ -13,6 +13,6 @@ class Admin::EmailsDownloadController < Admin::BaseController
   private
 
   def users_segment_emails_csv(users_segment)
-    UserSegments.send(users_segment).newsletter.pluck(:email).compact.join(',')
+    UserSegments.user_segment_emails(users_segment).join(',')
   end
 end

app/controllers/admin/newsletters_controller.rb

@@ -48,8 +48,8 @@ class Admin::NewslettersController < Admin::BaseController
     @newsletter = Newsletter.find(params[:id])
 
     if @newsletter.valid?
-      @newsletter.list_of_recipients.each do |recipient|
+      @newsletter.list_of_recipient_emails.each do |recipient_email|
-        Mailer.newsletter(@newsletter, recipient).deliver_later
+        Mailer.newsletter(@newsletter, recipient_email).deliver_later
       end
 
       @newsletter.update(sent_at: Time.current)

app/mailers/mailer.rb

@@ -126,9 +126,9 @@ class Mailer < ApplicationMailer
     end
   end
 
-  def newsletter(newsletter, recipient)
+  def newsletter(newsletter, recipient_email)
     @newsletter = newsletter
-    @email_to = recipient.email
+    @email_to = recipient_email
 
     mail(to: @email_to, from: @newsletter.from, subject: @newsletter.subject)
   end

app/models/newsletter.rb

@@ -8,8 +8,8 @@ class Newsletter < ActiveRecord::Base
 
   validates_format_of :from, :with => /@/
 
-  def list_of_recipients
+  def list_of_recipient_emails
-    UserSegments.send(segment_recipient).newsletter.select {|user| !user.email.nil? } if valid_segment_recipient?
+    UserSegments.user_segment_emails(segment_recipient) if valid_segment_recipient?
   end
 
   def valid_segment_recipient?

app/views/admin/newsletters/show.html.erb

@@ -2,7 +2,7 @@
 
 <h2><%= t("admin.newsletters.show.title") %></h2>
 
-<% recipients_count = @newsletter.valid_segment_recipient? ? @newsletter.list_of_recipients.count : 0 %>
+<% recipients_count = @newsletter.valid_segment_recipient? ? @newsletter.list_of_recipient_emails.count : 0 %>
 
 <div class="small-12 column">
   <div class="callout highlight">

lib/user_segments.rb

@@ -37,6 +37,10 @@ class UserSegments
     author_ids(current_budget_investments.winners.pluck(:author_id).uniq)
   end
 
+  def self.user_segment_emails(users_segment)
+    UserSegments.send(users_segment).newsletter.pluck(:email).compact
+  end
+
   private
 
   def self.current_budget_investments

spec/features/admin/emails/newsletters_spec.rb

@@ -133,7 +133,7 @@ feature "Admin newsletter emails" do
 
       click_link "Send"
 
-      total_users = newsletter.list_of_recipients.count
+      total_users = newsletter.list_of_recipient_emails.count
       page.accept_confirm("Are you sure you want to send this newsletter to #{total_users} users?")
 
       expect(page).to have_content "Newsletter sent successfully"

spec/models/newsletter_spec.rb

@@ -47,21 +47,20 @@ describe Newsletter do
     end
   end
 
-  describe '#list_of_recipients' do
+  describe '#list_of_recipient_emails' do
 
     before do
       create(:user, newsletter: true, email: 'newsletter_user@consul.dev')
-      no_news_user = create(:user, newsletter: false, email: 'no_news_user@consul.dev')
+      create(:user, newsletter: false, email: 'no_news_user@consul.dev')
-      erased_user = create(:user, email: 'erased_user@consul.dev')
+      create(:user, email: 'erased_user@consul.dev').erase
-      erased_user.erase
       newsletter.update(segment_recipient: 'all_users')
     end
 
     it 'returns list of recipients excluding users with disabled newsletter' do
-      expect(newsletter.list_of_recipients.count).to eq(1)
+      expect(newsletter.list_of_recipient_emails.count).to eq(1)
-      expect(newsletter.list_of_recipients.map(&:email)).to include('newsletter_user@consul.dev')
+      expect(newsletter.list_of_recipient_emails).to include('newsletter_user@consul.dev')
-      expect(newsletter.list_of_recipients.map(&:email)).not_to include('no_news_user@consul.dev')
+      expect(newsletter.list_of_recipient_emails).not_to include('no_news_user@consul.dev')
-      expect(newsletter.list_of_recipients.map(&:email)).not_to include('erased_user@consul.dev')
+      expect(newsletter.list_of_recipient_emails).not_to include('erased_user@consul.dev')
     end
   end
 end