Introduce class methods so CE constants can be easily overridden on EE

app/presenters/commit_status_presenter.rb

@@ -11,10 +11,16 @@ class CommitStatusPresenter < Gitlab::View::Presenter::Delegated
     runner_unsupported: 'Your runner is outdated, please upgrade your runner'
   }.freeze
+  private_constant :CALLOUT_FAILURE_MESSAGES
+
   presents :build
+  def self.callout_failure_messages
+    CALLOUT_FAILURE_MESSAGES
+  end
+
   def callout_failure_message
-    CALLOUT_FAILURE_MESSAGES.fetch(failure_reason.to_sym)
+    self.class.callout_failure_messages.fetch(failure_reason.to_sym)
   end
   def recoverable?

lib/gitlab/ci/status/build/failed.rb

@@ -13,6 +13,8 @@ module Gitlab
             runner_unsupported: 'unsupported runner'
           }.freeze
+          private_constant :REASONS
+
           def status_tooltip
             base_message
           end
@@ -25,6 +27,10 @@ module Gitlab
             build.failed?
           end
+          def self.reasons
+            REASONS
+          end
+
           private
           def base_message
@@ -36,7 +42,7 @@ module Gitlab
           end
           def failure_reason_message
-            REASONS.fetch(subject.failure_reason.to_sym)
+            self.class.reasons.fetch(subject.failure_reason.to_sym)
           end
         end
       end