Use enumerated status in persisted stage class

app/models/ci/stage.rb

 module Ci
   class Stage < ActiveRecord::Base
     extend Ci::Model
+    include HasStatus
+
+    enumerated_status!
 
     belongs_to :project
     belongs_to :pipeline

app/models/concerns/has_status.rb

@@ -8,6 +8,8 @@ module HasStatus
   ACTIVE_STATUSES = %w[pending running].freeze
   COMPLETED_STATUSES = %w[success failed canceled skipped].freeze
   ORDERED_STATUSES = %w[failed pending running manual canceled success skipped created].freeze
+  STATUSES_ENUM = { created: 0, pending: 1, running: 2, success: 3,
+                    failed: 4, canceled: 5, skipped: 6, manual: 7 }
 
   class_methods do
     def status_sql
@@ -54,6 +56,14 @@ module HasStatus
     def all_state_names
       state_machines.values.flat_map(&:states).flat_map { |s| s.map(&:name) }
     end
+
+    private
+
+    def enumerated_status!
+      @status_strategy = :enumerator
+
+      enum status: HasStatus::STATUSES_ENUM
+    end
   end
 
   included do

spec/factories/ci/stages.rb

@@ -15,4 +15,10 @@ FactoryGirl.define do
                                     warnings: warnings)
     end
   end
+
+  factory :ci_stage_entity, class: Ci::Stage do
+    project factory: :empty_project
+    pipeline factory: :ci_empty_pipeline
+    status 'pending'
+  end
 end

spec/migrations/migrate_stages_statuses_spec.rb

@@ -9,7 +9,6 @@ describe MigrateStagesStatuses, :migration do
 
   STATUSES = { created: 0, pending: 1, running: 2, success: 3,
                failed: 4, canceled: 5, skipped: 6, manual: 7 }
-  STAGES  = { test: 1, build: 2, deploy: 3}
 
   before do
     projects.create!(id: 1, name: 'gitlab1', path: 'gitlab1')
@@ -42,8 +41,10 @@ describe MigrateStagesStatuses, :migration do
   end
 
   def create_job(project:, pipeline:, stage:, status:, **opts)
+    stages  = { test: 1, build: 2, deploy: 3}
+
     jobs.create!(project_id: project, commit_id: pipeline,
-                 stage_idx: STAGES[stage.to_sym], stage: stage,
+                 stage_idx: stages[stage.to_sym], stage: stage,
                  status: status, **opts)
   end
 end

spec/models/ci/stage_spec.rb

+require 'spec_helper'
+
+describe Ci::Stage, :models do
+  describe '#status' do
+    context 'when stage is pending' do
+      let(:stage) { create(:ci_stage_entity, status: 'pending') }
+
+      it 'has a correct status value' do
+        expect(stage.status).to eq 'pending'
+      end
+    end
+
+    context 'when stage is success' do
+      let(:stage) { create(:ci_stage_entity, status: 'success') }
+
+      it 'has a correct status value' do
+        expect(stage.status).to eq 'success'
+      end
+    end
+  end
+end