diff --git a/features/step_definitions/metric_configuration_steps.rb b/features/step_definitions/metric_configuration_steps.rb
index 7f3106b..086ae3d 100644
--- a/features/step_definitions/metric_configuration_steps.rb
+++ b/features/step_definitions/metric_configuration_steps.rb
@@ -1,19 +1,19 @@
 Given(/^I have a sample metric configuration within the given mezuro configuration$/) do
   @metric_configuration = FactoryGirl.create(:metric_configuration,
-    {id: nil, configuration_id: @kalibro_configuration.id, reading_group_id: @reading_group.id} )
+    {kalibro_configuration_id: @kalibro_configuration.id, reading_group_id: @reading_group.id} )
 end
 
 Given(/^I have another metric configuration with code "(.*?)" within the given mezuro configuration$/) do |code|
   @another_metric_configuration = FactoryGirl.create(:metric_configuration,
-    {id: nil, configuration_id: @kalibro_configuration.id, reading_group_id: @reading_group.id, code: code} )
+    {kalibro_configuration_id: @kalibro_configuration.id, reading_group_id: @reading_group.id, code: code} )
 end
 
 When(/^I visit the sample metric configuration edit page$/) do
-  visit edit_kalibro_configuration_metric_configuration_path(@metric_configuration.configuration_id, @metric_configuration.id)
+  visit edit_kalibro_configuration_metric_configuration_path(@metric_configuration.kalibro_configuration_id, @metric_configuration.id)
 end
 
 When(/^I visit the sample metric configuration page$/) do
-  visit kalibro_configuration_metric_configuration_path(@metric_configuration.configuration_id, @metric_configuration.id)
+  visit kalibro_configuration_metric_configuration_path(@metric_configuration.kalibro_configuration_id, @metric_configuration.id)
 end
 
 When(/^I visit the sample metric configuration page$/) do
@@ -21,7 +21,7 @@ When(/^I visit the sample metric configuration page$/) do
 end
 
 Then(/^I am at the sample metric configuration page$/) do
-  visit kalibro_configuration_metric_configuration_path(@metric_configuration.configuration_id, @metric_configuration.id)
+  visit kalibro_configuration_metric_configuration_path(@metric_configuration.kalibro_configuration_id, @metric_configuration.id)
   expect(page).to have_content(@metric_configuration.metric.name)
   expect(page).to have_content("Ranges")
 end
diff --git a/features/step_definitions/repository_steps.rb b/features/step_definitions/repository_steps.rb
index 2babf64..41fcb68 100644
--- a/features/step_definitions/repository_steps.rb
+++ b/features/step_definitions/repository_steps.rb
@@ -3,8 +3,7 @@ Given(/^I have a sample configuration with native metrics but without ranges$/) 
   reading = FactoryGirl.create(:reading, {id: nil, group_id: reading_group.id})
   @kalibro_configuration = FactoryGirl.create(:kalibro_configuration, id: nil)
   metric_configuration = FactoryGirl.create(:metric_configuration,
-                                            {id: nil,
-                                             metric: FactoryGirl.build(:loc),
+                                            {metric: FactoryGirl.build(:loc),
                                              reading_group_id: reading_group.id,
                                              configuration_id: @kalibro_configuration.id,
                                              code: 'loc'})
@@ -15,12 +14,11 @@ Given(/^I have a sample configuration with native metrics$/) do
   reading = FactoryGirl.create(:reading, {id: nil, reading_group_id: reading_group.id})
 
   KalibroClient::Processor::MetricCollector.find('Analizo').supported_metrics.select { |x| not x.persisted? }.save
-  
+
 
   @kalibro_configuration = FactoryGirl.create(:kalibro_configuration, id: nil)
-  metric_configuration = FactoryGirl.create(:metric_configuration_with_snapshot,
-                                            {id: nil,
-                                             metric: FactoryGirl.build(:loc),
+  metric_configuration = FactoryGirl.create(:metric_configuration,
+                                            {metric: FactoryGirl.build(:loc),
                                              reading_group_id: reading_group.id,
                                              kalibro_configuration_id: @kalibro_configuration.id,
                                              code: 'loc'})
diff --git a/spec/controllers/base_metric_configurations_controller_spec.rb b/spec/controllers/base_metric_configurations_controller_spec.rb
index 8133a43..f1a1156 100644
--- a/spec/controllers/base_metric_configurations_controller_spec.rb
+++ b/spec/controllers/base_metric_configurations_controller_spec.rb
@@ -64,8 +64,8 @@ describe InheritsFromBaseMetricConfigurationsController, :type => :controller do
       sign_in FactoryGirl.create(:user)
     end
 
-    context 'when the current user owns the mezuro configuration' do
-      let!(:metric_configuration) { FactoryGirl.build(:metric_configuration) }
+    context 'when the current user owns the kalibro configuration' do
+      let!(:metric_configuration) { FactoryGirl.build(:metric_configuration_with_id) }
       before :each do
         subject.expects(:kalibro_configuration_owner?).returns true
         get :new, kalibro_configuration_id: kalibro_configuration.id
@@ -75,7 +75,7 @@ describe InheritsFromBaseMetricConfigurationsController, :type => :controller do
       it { is_expected.to respond_with(:success) }
     end
 
-    context "when the current user doesn't owns the mezuro configuration" do
+    context "when the current user doesn't owns the kalibro configuration" do
       before :each do
         get :new, kalibro_configuration_id: kalibro_configuration.id
       end
@@ -93,7 +93,7 @@ describe InheritsFromBaseMetricConfigurationsController, :type => :controller do
       sign_in FactoryGirl.create(:user)
     end
 
-    context 'when the current user owns the mezuro configuration' do
+    context 'when the current user owns the kalibro configuration' do
       before :each do
         subject.expects(:kalibro_configuration_owner?).returns true
       end
@@ -110,7 +110,7 @@ describe InheritsFromBaseMetricConfigurationsController, :type => :controller do
   end
 
   describe 'show' do
-    let(:metric_configuration) { FactoryGirl.build(:metric_configuration) }
+    let(:metric_configuration) { FactoryGirl.build(:metric_configuration_with_id) }
     let(:reading_group) { FactoryGirl.build(:reading_group) }
     let(:mezuro_range) { FactoryGirl.build(:mezuro_range) }
 
diff --git a/spec/controllers/compound_metric_configurations_controller_spec.rb b/spec/controllers/compound_metric_configurations_controller_spec.rb
index 4fe3b3b..743a429 100644
--- a/spec/controllers/compound_metric_configurations_controller_spec.rb
+++ b/spec/controllers/compound_metric_configurations_controller_spec.rb
@@ -8,7 +8,7 @@ describe CompoundMetricConfigurationsController, :type => :controller do
       sign_in FactoryGirl.create(:user)
     end
 
-    context 'when the current user owns the mezuro configuration' do
+    context 'when the current user owns the kalibro configuration' do
       let!(:metric_configuration) { FactoryGirl.build(:metric_configuration) }
       before :each do
         subject.expects(:kalibro_configuration_owner?).returns true
@@ -20,7 +20,7 @@ describe CompoundMetricConfigurationsController, :type => :controller do
       it { is_expected.to render_template(:new) }
     end
 
-    context "when the current user doesn't owns the mezuro configuration" do
+    context "when the current user doesn't owns the kalibro configuration" do
       before :each do
         get :new, kalibro_configuration_id: kalibro_configuration.id
       end
@@ -70,7 +70,7 @@ describe CompoundMetricConfigurationsController, :type => :controller do
   end
 
   describe 'show' do
-    let(:compound_metric_configuration) { FactoryGirl.build(:compound_metric_configuration) }
+    let(:compound_metric_configuration) { FactoryGirl.build(:compound_metric_configuration_with_id) }
     let(:reading_group) { FactoryGirl.build(:reading_group) }
     let(:mezuro_range) { FactoryGirl.build(:mezuro_range) }
 
@@ -86,7 +86,7 @@ describe CompoundMetricConfigurationsController, :type => :controller do
   end
 
   describe 'edit' do
-    let(:compound_metric_configuration) { FactoryGirl.build(:compound_metric_configuration) }
+    let(:compound_metric_configuration) { FactoryGirl.build(:compound_metric_configuration_with_id) }
 
     context 'with an User logged in' do
       before do
@@ -125,8 +125,8 @@ describe CompoundMetricConfigurationsController, :type => :controller do
   end
 
   describe 'update' do
-    let(:compound_metric_configuration) { FactoryGirl.build(:compound_metric_configuration) }
-    let(:metric_configuration_params) { Hash[FactoryGirl.attributes_for(:compound_metric_configuration).map { |k,v| [k.to_s, v.to_s] }] } #FIXME: Mocha is creating the expectations with strings, but FactoryGirl returns everything with sybols and integers
+    let(:compound_metric_configuration) { FactoryGirl.build(:compound_metric_configuration_with_id) }
+    let(:metric_configuration_params) { Hash[FactoryGirl.attributes_for(:compound_metric_configuration_with_id).map { |k,v| [k.to_s, v.to_s] }] } #FIXME: Mocha is creating the expectations with strings, but FactoryGirl returns everything with sybols and integers
 
     context 'when the user is logged in' do
       before do
diff --git a/spec/controllers/concerns/metric_configurations_concern_spec.rb b/spec/controllers/concerns/metric_configurations_concern_spec.rb
index 978b524..d2aec6b 100644
--- a/spec/controllers/concerns/metric_configurations_concern_spec.rb
+++ b/spec/controllers/concerns/metric_configurations_concern_spec.rb
@@ -2,7 +2,7 @@ require 'rails_helper'
 
 describe MetricConfigurationsConcern, type: :controller do
   describe 'set_metric_configuration' do
-    let! (:metric_configuration){ FactoryGirl.build(:metric_configuration) }
+    let! (:metric_configuration){ FactoryGirl.build(:metric_configuration_with_id) }
     let! (:metric_configurations_controller) { MetricConfigurationsController.new }
 
     before :each do
diff --git a/spec/controllers/metric_configurations_controller_spec.rb b/spec/controllers/metric_configurations_controller_spec.rb
index 306065a..49934e1 100644
--- a/spec/controllers/metric_configurations_controller_spec.rb
+++ b/spec/controllers/metric_configurations_controller_spec.rb
@@ -28,7 +28,7 @@ describe MetricConfigurationsController, :type => :controller do
       sign_in FactoryGirl.create(:user)
     end
 
-    context 'when the current user owns the mezuro configuration' do
+    context 'when the current user owns the kalibro configuration' do
       before :each do
         subject.expects(:kalibro_configuration_owner?).returns true
         KalibroClient::Entities::Processor::MetricCollectorDetails.expects(:find).with(metric_collector.name).returns(metric_collector)
@@ -40,7 +40,7 @@ describe MetricConfigurationsController, :type => :controller do
       it { is_expected.to render_template(:new) }
     end
 
-    context "when the current user doesn't owns the mezuro configuration" do
+    context "when the current user doesn't owns the kalibro configuration" do
       before :each do
         post :new, kalibro_configuration_id: kalibro_configuration.id, metric_name: "Lines of Code", metric_collector_name: metric_collector.name
       end
@@ -92,7 +92,7 @@ describe MetricConfigurationsController, :type => :controller do
   end
 
   describe 'show' do
-    let(:metric_configuration) { FactoryGirl.build(:metric_configuration) }
+    let(:metric_configuration) { FactoryGirl.build(:metric_configuration_with_id) }
     let(:reading_group) { FactoryGirl.build(:reading_group) }
     let(:mezuro_range) { FactoryGirl.build(:mezuro_range) }
 
@@ -108,7 +108,7 @@ describe MetricConfigurationsController, :type => :controller do
   end
 
   describe 'edit' do
-    let(:metric_configuration) { FactoryGirl.build(:metric_configuration) }
+    let(:metric_configuration) { FactoryGirl.build(:metric_configuration_with_id) }
 
     context 'with an User logged in' do
       before do
@@ -146,8 +146,8 @@ describe MetricConfigurationsController, :type => :controller do
   end
 
   describe 'update' do
-    let(:metric_configuration) { FactoryGirl.build(:metric_configuration) }
-    let(:metric_configuration_params) { Hash[FactoryGirl.attributes_for(:metric_configuration).map { |k,v| [k.to_s, v.to_s] }] } #FIXME: Mocha is creating the expectations with strings, but FactoryGirl returns everything with sybols and integers
+    let(:metric_configuration) { FactoryGirl.build(:metric_configuration_with_id) }
+    let(:metric_configuration_params) { metric_configuration.to_hash }
 
     context 'when the user is logged in' do
       before do
@@ -195,7 +195,7 @@ describe MetricConfigurationsController, :type => :controller do
 
 
   describe 'destroy' do
-    let(:metric_configuration) { FactoryGirl.build(:metric_configuration) }
+    let(:metric_configuration) { FactoryGirl.build(:metric_configuration_with_id) }
 
     context 'with an User logged in' do
       before do
diff --git a/spec/controllers/mezuro_configurations_controller_spec.rb b/spec/controllers/mezuro_configurations_controller_spec.rb
index 9f535fc..43835fd 100644
--- a/spec/controllers/mezuro_configurations_controller_spec.rb
+++ b/spec/controllers/mezuro_configurations_controller_spec.rb
@@ -61,7 +61,7 @@ describe KalibroConfigurationsController, :type => :controller do
 
   describe 'show' do
   	let(:kalibro_configuration) { FactoryGirl.build(:kalibro_configuration) }
-  	let(:metric_configuration) { FactoryGirl.build(:metric_configuration) }
+  	let(:metric_configuration) { FactoryGirl.build(:metric_configuration_with_id) }
 
     before :each do
       kalibro_configuration.expects(:metric_configurations).returns(metric_configuration)
diff --git a/spec/controllers/mezuro_ranges_controller_spec.rb b/spec/controllers/mezuro_ranges_controller_spec.rb
index 7de455c..c09987a 100644
--- a/spec/controllers/mezuro_ranges_controller_spec.rb
+++ b/spec/controllers/mezuro_ranges_controller_spec.rb
@@ -2,7 +2,7 @@ require 'rails_helper'
 
 describe MezuroRangesController, :type => :controller do
   let(:mezuro_range) { FactoryGirl.build(:mezuro_range, id: 1) }
-  let(:metric_configuration) { FactoryGirl.build(:metric_configuration) }
+  let(:metric_configuration) { FactoryGirl.build(:metric_configuration_with_id) }
 
   describe 'new' do
     let(:kalibro_configuration) { FactoryGirl.build(:kalibro_configuration) }
@@ -109,7 +109,7 @@ describe MezuroRangesController, :type => :controller do
   end
 
   describe 'edit' do
-    let(:metric_configuration) { FactoryGirl.build(:metric_configuration) }
+    let(:metric_configuration) { FactoryGirl.build(:metric_configuration_with_id) }
     let(:mezuro_range) { FactoryGirl.build(:mezuro_range, id: 1, metric_configuration_id: metric_configuration.id) }
     let(:reading) { FactoryGirl.build(:reading, reading_group_id: metric_configuration.reading_group_id) }
 
@@ -153,7 +153,7 @@ describe MezuroRangesController, :type => :controller do
   end
 
   describe 'update' do
-    let(:metric_configuration) { FactoryGirl.build(:metric_configuration) }
+    let(:metric_configuration) { FactoryGirl.build(:metric_configuration_with_id) }
     let(:mezuro_range) { FactoryGirl.build(:mezuro_range, id: 1, metric_configuration_id: metric_configuration.id) }
     let(:mezuro_range_params) { Hash[FactoryGirl.attributes_for(:mezuro_range).map { |k,v| [k.to_s, v.to_s] }] } #FIXME: Mocha is creating the expectations with strings, but FactoryGirl returns everything with sybols and integers
     let(:reading) { FactoryGirl.build(:reading, reading_group_id: metric_configuration.reading_group_id) }
diff --git a/spec/factories/metric_configurations.rb b/spec/factories/metric_configurations.rb
index bbce743..653dee2 100644
--- a/spec/factories/metric_configurations.rb
+++ b/spec/factories/metric_configurations.rb
@@ -1,23 +1,33 @@
 FactoryGirl.define do
   factory :metric_configuration, class: MetricConfiguration do
-    id 1
     metric {FactoryGirl.build(:metric, code: 'total_abstract_classes')}
     weight 1
     aggregation_form "AVERAGE"
     reading_group_id 1
     kalibro_configuration_id 1
+
+    trait :with_id do
+      id 1
+    end
+
+    factory :metric_configuration_with_id, traits: [:with_id]
   end
 
   factory :compound_metric_configuration, class: MetricConfiguration do
-    id 1
     metric { FactoryGirl.build(:compound_metric, script: 'native*2;', code: 'compound') }
     weight 1
     aggregation_form "AVERAGE"
     reading_group_id 1
     kalibro_configuration_id 1
+
+    trait :with_id do
+      id 1
+    end
+
+    factory :compound_metric_configuration_with_id, traits: [:with_id]
   end
 
-  factory :another_metric_configuration, class: MetricConfiguration do
+  factory :another_metric_configuration_with_id, class: MetricConfiguration do
     id 1
     metric {FactoryGirl.build(:metric, code: 'total_modules')}
     weight 1
diff --git a/spec/factories/metric_results.rb b/spec/factories/metric_results.rb
index 4f14154..046995a 100644
--- a/spec/factories/metric_results.rb
+++ b/spec/factories/metric_results.rb
@@ -17,7 +17,7 @@
 FactoryGirl.define do
   factory :metric_result, class: KalibroClient::Entities::Processor::MetricResult do
     id  "42"
-    metric_configuration { FactoryGirl.build(:metric_configuration) }
+    metric_configuration { FactoryGirl.build(:metric_configuration_with_id) }
     value "10.0"
     aggregated_value "21"
   end
diff --git a/spec/helpers/metric_configurations_helper_spec.rb b/spec/helpers/metric_configurations_helper_spec.rb
index 4d85143..ed9662f 100644
--- a/spec/helpers/metric_configurations_helper_spec.rb
+++ b/spec/helpers/metric_configurations_helper_spec.rb
@@ -21,7 +21,7 @@ describe MetricConfigurationsHelper, :type => :helper do
   end
 
   describe 'native_metrics_of' do
-    let! (:metric_configuration) { FactoryGirl.build(:metric_configuration) }
+    let! (:metric_configuration) { FactoryGirl.build(:metric_configuration_with_id) }
 
     before :each do
       MetricConfiguration.expects(:metric_configurations_of).with(metric_configuration.kalibro_configuration_id).returns([metric_configuration])
diff --git a/spec/helpers/mezuro_configurations_helper_spec.rb b/spec/helpers/mezuro_configurations_helper_spec.rb
index ea93678..966c03d 100644
--- a/spec/helpers/mezuro_configurations_helper_spec.rb
+++ b/spec/helpers/mezuro_configurations_helper_spec.rb
@@ -44,14 +44,14 @@ describe KalibroConfigurationsHelper, :type => :helper do
 
   describe 'link to edit form' do
     context 'when the metric is native' do
-      let(:metric_configuration) { FactoryGirl.build(:metric_configuration) }
+      let(:metric_configuration) { FactoryGirl.build(:metric_configuration_with_id) }
       let(:response_link) {"<a class=\"btn btn-info\" href=\"/kalibro_configurations/#{metric_configuration.kalibro_configuration_id}/metric_configurations/#{metric_configuration.id}/edit\">Edit</a>"}
 
       it { expect(helper.link_to_edit_form(metric_configuration, metric_configuration.kalibro_configuration_id)).to eq(response_link) }
     end
 
     context 'when the metric is compound' do
-      let(:compound_metric_configuration) { FactoryGirl.build(:compound_metric_configuration) }
+      let(:compound_metric_configuration) { FactoryGirl.build(:compound_metric_configuration_with_id) }
       let(:response_link) {"<a class=\"btn btn-info\" href=\"/kalibro_configurations/#{compound_metric_configuration.kalibro_configuration_id}/compound_metric_configurations/#{compound_metric_configuration.id}/edit\">Edit</a>"}
 
       it { expect(helper.link_to_edit_form(compound_metric_configuration, compound_metric_configuration.kalibro_configuration_id)).to eq(response_link) }
@@ -60,14 +60,14 @@ describe KalibroConfigurationsHelper, :type => :helper do
 
   describe 'link to show page' do
     context 'when the metric is native' do
-      let(:metric_configuration) { FactoryGirl.build(:metric_configuration) }
+      let(:metric_configuration) { FactoryGirl.build(:metric_configuration_with_id) }
       let(:response_link) {"<a class=\"btn btn-info\" href=\"/kalibro_configurations/#{metric_configuration.kalibro_configuration_id}/metric_configurations/#{metric_configuration.id}\">Show</a>"}
 
       it { expect(helper.link_to_show_page(metric_configuration, metric_configuration.kalibro_configuration_id)).to eq(response_link) }
     end
 
     context 'when the metric is compound' do
-      let(:compound_metric_configuration) { FactoryGirl.build(:compound_metric_configuration) }
+      let(:compound_metric_configuration) { FactoryGirl.build(:compound_metric_configuration_with_id) }
       let(:response_link) {"<a class=\"btn btn-info\" href=\"/kalibro_configurations/#{compound_metric_configuration.kalibro_configuration_id}/compound_metric_configurations/#{compound_metric_configuration.id}\">Show</a>"}
 
       it { expect(helper.link_to_show_page(compound_metric_configuration, compound_metric_configuration.kalibro_configuration_id)).to eq(response_link) }
diff --git a/spec/helpers/processings_helper_spec.rb b/spec/helpers/processings_helper_spec.rb
index fc607a4..ea3a82d 100644
--- a/spec/helpers/processings_helper_spec.rb
+++ b/spec/helpers/processings_helper_spec.rb
@@ -14,7 +14,7 @@ describe ProcessingsHelper, :type => :helper do
   end
 
   describe 'find_range_snapshot' do
-    let(:metric_configuration) { FactoryGirl.build(:metric_configuration)}
+    let(:metric_configuration) { FactoryGirl.build(:metric_configuration_with_id)}
     let(:metric_result) { FactoryGirl.build(:metric_result, {value: 6.0, metric_configuration: metric_configuration})}
     let(:range_snapshot_1_to_5) { FactoryGirl.build(:range_snapshot, {beginning: 1.0, end: 5.0}) }
     let(:range_snapshot_5dot1_to_10) { FactoryGirl.build(:range_snapshot, {beginning: 5.1, end: 10.0}) }
diff --git a/spec/models/module_result_spec.rb b/spec/models/module_result_spec.rb
index 42f0026..b3ff15a 100644
--- a/spec/models/module_result_spec.rb
+++ b/spec/models/module_result_spec.rb
@@ -3,10 +3,10 @@ require 'rails_helper'
 describe ModuleResult, :type => :model do
   describe 'methods' do
     subject { FactoryGirl.build(:module_result) }
-    
+
     describe 'metric_history' do
       let(:date_module_result) {FactoryGirl.build(:date_module_result)}
-      let(:metric_configuration) { FactoryGirl.build(:another_metric_configuration) }
+      let(:metric_configuration) { FactoryGirl.build(:another_metric_configuration_with_id) }
       let!(:metric_result) { FactoryGirl.build(:metric_result, metric_configuration: metric_configuration) }
       let(:processing) {FactoryGirl.build(:processing)}
       let(:repository) {FactoryGirl.build(:repository)}
--
libgit2 0.21.2