Add initial implmentation for core success status

lib/gitlab/ci/status/core/success.rb

@@ -2,6 +2,13 @@ module Gitlab::Ci
   module Status
     module Core
       class Success
+        def label
+          'passed'
+        end
+
+        def icon
+          'success'
+        end
       end
     end
   end

spec/lib/gitlab/ci/status/core/success_spec.rb

+require 'spec_helper'
+
+describe Gitlab::Ci::Status::Core::Success do
+  describe '#label' do
+    it { expect(subject.label).to eq 'passed' }
+  end
+
+  describe '#icon' do
+    it { expect(subject.icon).to eq 'success' }
+  end
+end