Simplify noop reporter

lib/mutant/reporter/cli/report/mutation.rb

@@ -99,12 +99,22 @@ module Mutant
           #
           def report_noop
             info('NOOP MUTATION TESTS FAILED!')
-            killers.reject(&:success?).map(&:report).map(&:test_report).each do |report|
+            noop_reports.each do |report|
               puts(report.test.identification)
               puts(report.output)
             end
           end
 
+          # Return test noop reports
+          #
+          # @return [Enumerable<Test::Report>]
+          #
+          # @api private
+          #
+          def noop_reports
+            killers.reject(&:success?).map(&:report).map(&:test_report)
+          end
+
         end # Mutation
       end # Report
     end # CLI