Add feature specs for a pipeline security page

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

ee/spec/features/projects/pipelines/pipeline_spec.rb

+require 'spec_helper'
+
+describe 'Pipeline', :js do
+  let(:project) { create(:project) }
+  let(:user) { create(:user) }
+
+  before do
+    sign_in(user)
+    project.add_developer(user)
+  end
+
+  describe 'GET /:project/pipelines/:id/security' do
+    let(:project) { create(:project, :repository) }
+    let(:pipeline) { create(:ci_pipeline, project: project, ref: 'master', sha: project.commit.id) }
+
+    let(:build) do
+      create(
+        :ci_build,
+        :artifacts,
+        name: 'sast',
+        pipeline: pipeline,
+        options: {
+          artifacts: {
+            paths: [Ci::Build::SAST_FILE]
+          }
+        }
+      )
+    end
+
+    context 'when there is a sast artifact' do
+      before do
+        build
+
+        visit security_project_pipeline_path(project, pipeline)
+      end
+
+      it 'shows jobs tab pane as active' do
+        expect(page).to have_content('Security report')
+        expect(page).to have_css('#js-tab-security')
+      end
+
+      it 'shows security report' do
+        expect(page).to have_content('SAST detected no security vulnerabilities')
+      end
+    end
+
+    context 'without sast artifact' do
+      before do
+        visit security_project_pipeline_path(project, pipeline)
+      end
+
+      it 'displays the pipeline graph' do
+        expect(current_path).to eq(pipeline_path(pipeline))
+        expect(page).not_to have_content('Security report')
+      end
+    end
+  end
+end