Refactor builds badge, encapsulate inside a class

app/controllers/projects/badges_controller.rb

@@ -2,11 +2,12 @@ class Projects::BadgesController < Projects::ApplicationController
   before_action :no_cache_headers
 
   def build
+    badge = Gitlab::Badge::Build.new(project, params[:ref])
+
     respond_to do |format|
       format.html { render_404 }
       format.svg do
-        image = Ci::ImageForBuildService.new.execute(project, ref: params[:ref])
-        send_file(image.path, filename: image.name, disposition: 'inline', type: 'image/svg+xml')
+        send_data(badge.data, type: badge.type, disposition: 'inline')
       end
     end
   end

lib/gitlab/badge/build.rb

+module Gitlab
+  module Badge
+    ##
+    # Build badge
+    #
+    class Build
+      def initialize(project, ref)
+        @image = ::Ci::ImageForBuildService.new.execute(project, ref: ref)
+      end
+
+      def to_s
+        @image[:name].sub(/\.svg$/, '')
+      end
+
+      def type
+        'image/svg+xml'
+      end
+
+      def data
+        File.read(@image[:path])
+      end
+    end
+  end
+end

spec/lib/gitlab/badge/build_spec.rb

+require 'spec_helper'
+
+describe Gitlab::Badge::Build do
+  let(:project) { create(:project) }
+  let(:sha) { project.commit.sha }
+  let(:ci_commit) { create(:ci_commit, project: project, sha: sha) }
+  let(:badge) { described_class.new(project, 'master') }
+
+  let!(:build) { create(:ci_build, commit: ci_commit) }
+
+  describe '#type' do
+    subject { badge.type }
+    it { is_expected.to eq 'image/svg+xml' }
+  end
+
+  context 'build success' do
+    before { build.success! }
+
+    describe '#to_s' do
+      subject { badge.to_s }
+      it { is_expected.to eq 'build-success' }
+    end
+
+    describe '#data' do
+      let(:data) { badge.data }
+      let(:xml) { Nokogiri::XML.parse(data) }
+
+      it 'contains infromation about success' do
+        expect(xml.at(%Q{text:contains("success")})).to be_truthy
+      end
+    end
+  end
+end