Refactor action arguments checks

lib/producer/core/action.rb

@@ -30,6 +30,12 @@ module Producer
       def inspect_arguments
         @arguments.inspect[0, INSPECT_ARGUMENTS_SUM_LEN - name.length]
       end
+
+      def check_arguments_size!(size)
+        if arguments.compact.size != size
+          fail ArgumentError, '`%s\' action requires %d arguments' % [name, size]
+        end
+      end
     end
   end
 end

lib/producer/core/actions/file_append.rb

@@ -3,10 +3,7 @@ module Producer
     module Actions
       class FileAppend < Action
         def setup
-          if arguments.compact.size != 2
+          check_arguments_size! 2
-            fail ArgumentError, '`%s\' action requires 2 arguments' % name
-          end
-
           @path, @content = arguments
         end
 

lib/producer/core/actions/file_writer.rb

@@ -3,10 +3,7 @@ module Producer
     module Actions
       class FileWriter < Action
         def setup
-          if arguments.compact.size != 2
+          check_arguments_size! 2
-            fail ArgumentError, '`%s\' action requires 2 arguments' % name
-          end
-
           @path, @content         = arguments
           @options[:permissions]  = @options.delete :mode if options.key? :mode
           @options[:owner]        = @options.delete :user if options.key? :user