Remove duplicate email received

db/migrate/20170215102943_remove_duplicate_email_received.rb

@@ -0,0 +1,11 @@
+class RemoveDuplicateEmailReceived < ActiveRecord::Migration[5.0]
+  def change
+     all_mails = MailReceived.all
+     groupped = all_mails.group_by { |m| m.procedure_id }
+     filtered = groupped.reject { |k, v| v.length < 2 }
+     filtered.each do |k, duplicate_mails|
+       duplicate_mails.pop
+       duplicate_mails.each(&:destroy)
+     end
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20170125152856) do
+ActiveRecord::Schema.define(version: 20170215102943) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"

spec/migrations/remove_duplicate_email_received_spec.rb

@@ -0,0 +1,25 @@
+load 'spec/spec_helper.rb'
+load 'db/migrate/20170215102943_remove_duplicate_email_received.rb'
+
+describe RemoveDuplicateEmailReceived do
+  context 'with one procedure and one associated mail_received' do
+    let!(:procedure) { create(:procedure) }
+
+    it 'keeps the procedure mails' do
+      RemoveDuplicateEmailReceived.new.change
+      expect(MailReceived.count).to eq(1)
+    end
+
+    context 'and another mail_received' do
+      before :each do
+        MailReceived.create!(procedure: procedure)
+      end
+
+      it 'destroys the unecessary maiL_received' do
+        RemoveDuplicateEmailReceived.new.change
+        expect(MailReceived.count).to eq(1)
+        expect(procedure.mail_received).not_to be_nil
+      end
+    end
+  end
+end