Add tests for stage API endpoint

app/controllers/projects/pipelines_controller.rb

@@ -42,9 +42,7 @@ class Projects::PipelinesController < Projects::ApplicationController
   end
 
   def stage
-    @stage = pipeline.stages.find do |stage|
-      stage.name == params[:stage]
-    end
+    @stage = pipeline.stage(params[:stage])
     return not_found unless @stage
 
     respond_to do |format|

app/models/ci/pipeline.rb

@@ -116,6 +116,11 @@ module Ci
       where.not(duration: nil).sum(:duration)
     end
 
+    def stage(name)
+      stage = Ci::Stage.new(self, name: name)
+      stage unless stage.statuses_count.zero?
+    end
+
     def stages_count
       statuses.select(:stage).distinct.count
     end

app/models/ci/stage.rb

@@ -18,6 +18,10 @@ module Ci
       name
     end
 
+    def statuses_count
+      @statuses_count ||= statuses.count
+    end
+
     def status
       @status ||= statuses.latest.status
     end

spec/features/projects/pipelines/pipelines_spec.rb

@@ -152,6 +152,35 @@ describe "Pipelines" do
     end
   end
 
+  describe 'GET /:project/pipelines/stage?name=stage' do
+    let!(:pipeline) do
+      create(:ci_empty_pipeline, project: project, ref: 'master',
+        status: 'running')
+    end
+
+    context 'when accessing existing stage' do
+      let!(:build) do
+        create(:ci_build, pipeline: pipeline, stage: 'build')
+      end
+
+      before do
+        visit stage_namespace_project_pipeline_path(
+          project.namespace, project, pipeline, format: :json, stage: 'build')
+      end
+
+      it { expect(page).to have_http_status(:ok) }
+    end
+
+    context 'when accessing unknown stage' do
+      before do
+        visit stage_namespace_project_pipeline_path(
+          project.namespace, project, pipeline, format: :json, stage: 'test')
+      end
+
+      it { expect(page).to have_http_status(:not_found) }
+    end
+  end
+
   describe 'POST /:project/pipelines' do
     let(:project) { create(:project) }
 

spec/models/ci/pipeline_spec.rb

@@ -175,6 +175,26 @@ describe Ci::Pipeline, models: true do
     end
   end
 
+  describe '#stage' do
+    subject { pipeline.stage('test') }
+
+    context 'with status in stage' do
+      let!(:status) { create(:commit_status, pipeline: pipeline, stage: 'test') }
+
+      it 'return stage object' do
+        is_expected.to be_a(Ci::Stage)
+      end
+    end
+
+    context 'without status in stage' do
+      let!(:status) { create(:commit_status, pipeline: pipeline, stage: 'build') }
+
+      it 'return stage object' do
+        is_expected.to be_nil
+      end
+    end
+  end
+
   describe 'state machine' do
     let(:current) { Time.now.change(usec: 0) }
     let(:build) { create_build('build1', 0) }

spec/models/ci/stage_spec.rb

@@ -28,6 +28,17 @@ describe Ci::Stage, models: true do
     end
   end
 
+  describe '#statuses_count' do
+    let!(:stage_build) { create_job(:ci_build) }
+    let!(:other_build) { create_job(:ci_build, stage: 'other stage') }
+
+    subject { stage.statuses_count }
+
+    it "statuses only from current stage" do
+      is_expected.to eq(1)
+    end
+  end
+
   describe '#builds' do
     let!(:stage_build) { create_job(:ci_build) }
     let!(:commit_status) { create_job(:commit_status) }