1 files changed, 51 insertions, 0 deletions
diff --git a/spec/support/data_modifier.rb b/spec/support/data_modifier.rb
new file mode 100644
index 000000000..7fb0db6f6
--- /dev/null
+++ b/spec/support/data_modifier.rb
@@ -0,0 +1,51 @@
+require_relative 'data_modifier/enum'
+module Support
+  module DataModifier
+    module InstanceMethods
+      CannotModify = Class.new RuntimeError
+
+      def advance_values(atts, *keys)
+        keys.inject(atts){ |h, k| h.merge( k => atts[k].next) }
+      end
+
+      # return array of atts wich each value modified, unboxing
+      # values if needed
+      def modify_atts(base_atts)
+        base_atts.keys.map do | key |
+          modify_att base_atts, key
+        end.compact
+      end
+
+      private
+      def modify_att atts, key
+        atts.merge(key => modify_value(atts[key]))
+      rescue CannotModify
+        nil
+      end
+      def modify_value value
+        case value
+        when String
+          "#{value}."
+        when Fixnum
+          value + 1
+        when TrueClass
+          false
+        when FalseClass
+          true
+        when Float
+          value * 1.1
+        when Date
+          value + 1.day
+        when Box
+          value.next.value
+        else
+          raise CannotModify
+        end
+      end
+    end
+  end
+end
+
+RSpec.configure do | c |
+  c.include Support::DataModifier::InstanceMethods, type: :checksum
+end