register costs so that it can cause a latest project activity (#237)

db/migrate/20160504070128_add_index_for_latest_cost_activity.rb

@@ -0,0 +1,5 @@
+class AddIndexForLatestCostActivity < ActiveRecord::Migration
+  def change
+    add_index :cost_objects, [:project_id, :updated_on]
+  end
+end

lib/open_project/costs/engine.rb

@@ -279,6 +279,11 @@ module OpenProject::Costs
       ActionView::Helpers::NumberHelper.send(:include, OpenProject::Costs::Patches::NumberHelperPatch)
     end
 
+    initializer 'costs.register_latest_project_activity' do
+      Project.register_latest_project_activity on: ::CostObject,
+                                               attribute: :updated_on
+    end
+
     config.to_prepare do
       # loading the class so that acts_as_journalized gets registered
       VariableCostObject

spec/models/project/activity_spec.rb

@@ -0,0 +1,80 @@
+#-- copyright
+# OpenProject Costs Plugin
+#
+# Copyright (C) 2009 - 2014 the OpenProject Foundation (OPF)
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# version 3.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#++
+
+require 'spec_helper'
+
+describe Project::Activity, type: :model do
+  let(:project) do
+    FactoryGirl.create(:project)
+  end
+
+  let(:initial_time) { Time.now }
+
+  let(:cost_object) do
+    FactoryGirl.create(:cost_object,
+                       project: project)
+  end
+
+  let(:cost_object2) do
+    FactoryGirl.create(:cost_object,
+                       project: project)
+  end
+
+  let(:work_package) do
+    FactoryGirl.create(:work_package,
+                       project: project)
+  end
+
+  def latest_activity
+    Project.with_latest_activity.find(project.id).latest_activity_at
+  end
+
+  describe '.with_latest_activity' do
+    it 'is the latest cost_object update' do
+      cost_object.update_attribute(:updated_on, initial_time - 10.seconds)
+      cost_object2.update_attribute(:updated_on, initial_time - 20.seconds)
+      cost_object.reload
+      cost_object2.reload
+
+      expect(latest_activity).to eql cost_object.updated_on
+    end
+
+    it 'takes the time stamp of the latest activity across models' do
+      work_package.update_attribute(:updated_at, initial_time - 10.seconds)
+      cost_object.update_attribute(:updated_on, initial_time - 20.seconds)
+
+      work_package.reload
+      cost_object.reload
+
+      # Order:
+      # work_package
+      # cost_object
+
+      expect(latest_activity).to eql work_package.updated_at
+
+      work_package.update_attribute(:updated_at, cost_object.updated_on - 10.seconds)
+
+      # Order:
+      # cost_object
+      # work_package
+
+      expect(latest_activity).to eql cost_object.updated_on
+    end
+  end
+end