lib/prezzo/calculator.rb in prezzo-0.1.0 vs lib/prezzo/calculator.rb in prezzo-0.2.0

@@ -1,15 +1,22 @@
 module Prezzo
-  class Calculator
+  module Calculator
     def initialize(context = {})
-      @context = context
+      @context = validated!(context)
     end
 
     def calculate
-      0
+      raise "Calculate not implemented"
     end
 
     private
+
+    def validated!(context)
+      raise "Empty Context" if context.nil?
+      raise "Invalid Context" if context.respond_to?(:valid?) && !context.valid?
+
+      context
+    end
 
     def context
       @context
     end
   end