Enable RSpec/BeforeAfterAll rule and fix all issues

This cop tries to avoid state leaking between examples. The fixes done on the code don't follow the suggested path, since the usage of `before(:all)` was not really useful. By using RSpec's `let` method we achieve same goals but with much better and readable tests.

Check Cop description at http://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/BeforeAfterAll

spec/lib/manager_authenticator_spec.rb

@@ -1,66 +1,60 @@
 require 'rails_helper'
 
 describe ManagerAuthenticator do
+  let(:authenticator) { ManagerAuthenticator.new(login: "JJB033", clave_usuario: "31415926", fecha_conexion: "20151031135905") }
+
   describe 'initialization params' do
     it 'should cause auth to return false if blank login' do
-      authenticator = ManagerAuthenticator.new(login: "", clave_usuario: "31415926", fecha_conexion: "20151031135905")
-      expect(authenticator.auth).to be false
+      blank_login_authenticator = ManagerAuthenticator.new(login: "", clave_usuario: "31415926", fecha_conexion: "20151031135905")
+      expect(blank_login_authenticator.auth).to be false
     end
 
     it 'should cause auth to return false if blank user_key' do
-      authenticator = ManagerAuthenticator.new(login: "JJB033", clave_usuario: "", fecha_conexion: "20151031135905")
-      expect(authenticator.auth).to be false
+      blank_user_key_authenticator = ManagerAuthenticator.new(login: "JJB033", clave_usuario: "", fecha_conexion: "20151031135905")
+      expect(blank_user_key_authenticator.auth).to be false
     end
 
     it 'should cause auth to return false if blank date' do
-      authenticator = ManagerAuthenticator.new(login: "JJB033", clave_usuario: "31415926", fecha_conexion: "")
-      expect(authenticator.auth).to be false
+      blank_date_authenticator = ManagerAuthenticator.new(login: "JJB033", clave_usuario: "31415926", fecha_conexion: "")
+      expect(blank_date_authenticator.auth).to be false
     end
   end
 
   describe '#auth' do
-    before(:all) do
-      @authenticator = ManagerAuthenticator.new(login: "JJB033", clave_usuario: "31415926", fecha_conexion: "20151031135905")
-    end
-
     it 'should return false if not manager_exists' do
-      allow(@authenticator).to receive(:manager_exists?).and_return(false)
-      allow(@authenticator).to receive(:application_authorized?).and_return(true)
+      allow(authenticator).to receive(:manager_exists?).and_return(false)
+      allow(authenticator).to receive(:application_authorized?).and_return(true)
 
-      expect(@authenticator.auth).to be false
+      expect(authenticator.auth).to be false
     end
 
     it 'should return false if not application_authorized' do
-      allow(@authenticator).to receive(:manager_exists?).and_return(true)
-      allow(@authenticator).to receive(:application_authorized?).and_return(false)
+      allow(authenticator).to receive(:manager_exists?).and_return(true)
+      allow(authenticator).to receive(:application_authorized?).and_return(false)
 
-      expect(@authenticator.auth).to be false
+      expect(authenticator.auth).to be false
     end
 
     it 'should return ok if manager_exists and application_authorized' do
-      allow(@authenticator).to receive(:manager_exists?).and_return(true)
-      allow(@authenticator).to receive(:application_authorized?).and_return(true)
+      allow(authenticator).to receive(:manager_exists?).and_return(true)
+      allow(authenticator).to receive(:application_authorized?).and_return(true)
 
-      expect(@authenticator.auth).to be_truthy
+      expect(authenticator.auth).to be_truthy
     end
   end
 
   describe 'SOAP' do
-    before(:all) do
-      @authenticator = ManagerAuthenticator.new(login: "JJB033", clave_usuario: "31415926", fecha_conexion: "20151031135905")
-    end
-
     it 'should call the verification user method' do
       message = { ub: {user_key: "31415926", date: "20151031135905"} }
-      allow(@authenticator).to receive(:application_authorized?).and_return(true)
-      expect(@authenticator.send(:client)).to receive(:call).with(:get_status_user_data, message: message)
-      @authenticator.auth
+      allow(authenticator).to receive(:application_authorized?).and_return(true)
+      expect(authenticator.send(:client)).to receive(:call).with(:get_status_user_data, message: message)
+      authenticator.auth
     end
 
     it 'should call the permissions check method' do
-      allow(@authenticator).to receive(:manager_exists?).and_return(true)
-      expect(@authenticator.send(:client)).to receive(:call).with(:get_applications_user_list, message: { ub: {user_key: "31415926"} })
-      @authenticator.auth
+      allow(authenticator).to receive(:manager_exists?).and_return(true)
+      expect(authenticator.send(:client)).to receive(:call).with(:get_applications_user_list, message: { ub: {user_key: "31415926"} })
+      authenticator.auth
     end
   end
 end