Add status entity prototype and expose in pipeline

app/serializers/pipeline_entity.rb

@@ -12,7 +12,7 @@ class PipelineEntity < Grape::Entity
   end
 
   expose :details do
-    expose :status
+    expose :detailed_status, as: :status, using: StatusEntity
     expose :duration
     expose :finished_at
     expose :stages_with_statuses, as: :stages, using: PipelineStageEntity

app/serializers/status_entity.rb

+class StatusEntity < Grape::Entity
+  include RequestAwareEntity
+
+  expose :icon, :text, :label, :title
+
+  expose :has_details?, as: :has_details
+  expose :details_path
+end

spec/serializers/status_entity_spec.rb

+require 'spec_helper'
+
+describe StatusEntity do
+  let(:entity) do
+    described_class.new(status)
+  end
+
+  let(:status) do # TODO, add statuses factory
+    Gitlab::Ci::Status::Success.new(double('object'))
+  end
+
+  before do
+    allow(status).to receive(:has_details?).and_return(true)
+    allow(status).to receive(:details_path).and_return('some/path')
+  end
+
+  subject { entity.as_json }
+
+  it 'contains status details' do
+    expect(subject).to include :text, :icon, :label, :title
+    expect(subject).to include :has_details
+    expect(subject).to include :details_path
+  end
+end