extracted boolean validation logic into stand-alone validator

lib/active_model/validations/boolean_presence_validator.rb

@@ -0,0 +1,12 @@
+module ActiveModel
+  module Validations
+    class BooleanPresenceValidator < EachValidator
+      def validate(record)
+        [attributes].flatten.each do |attribute|
+          value = record.send(:read_attribute_for_validation, attribute)
+          record.errors.add(attribute, nil, options) unless [false, true].include?(value)
+        end
+      end
+    end
+  end
+end