Have StripeObject#update_attributes reflect behavior of accessors

This dials down the safety of `StripeObject`'s `#update_attributes`
method so that it allows properties to be assigned that it doesn't yet
know about. We're doing this for a few reasons:

1. To reflect the current behavior of accessors (i.e. `obj.name = ...`)
   through `method_missing`.
2. To allow `#update_attributes` to assign properties on new projects
   that don't yet know their schema from an API call.

Fixes #324.

lib/stripe/api_operations/update.rb

@@ -20,7 +20,7 @@ module Stripe
         # We started unintentionally (sort of) allowing attributes send to
         # +save+ to override values used during the update. So as not to break
         # the API, this makes that official here.
-        update_attributes_with_options(params, :raise_error => false)
+        update_attributes(params)
 
         # Now remove any parameters that look like object attributes.
         params = params.reject { |k, _| respond_to?(k) }

lib/stripe/stripe_object.rb

@@ -63,7 +63,7 @@ module Stripe
         @unsaved_values.delete(k)
       end
 
-      update_attributes_with_options(values, :opts => opts)
+      update_attributes(values, :opts => opts)
       values.each do |k, _|
         @transient_values.delete(k)
         @unsaved_values.delete(k)
@@ -73,8 +73,25 @@ module Stripe
     end
 
     # Mass assigns attributes on the model.
-    def update_attributes(values)
-      update_attributes_with_options(values, {})
+    #
+    # This is a version of +update_attributes+ that takes some extra options
+    # for internal use.
+    #
+    # ==== Attributes
+    #
+    # * +values+ - Hash of values to use to update the current attributes of
+    #   the object.
+    #
+    # ==== Options
+    #
+    # * +:opts+ Options for StripeObject like an API key.
+    # * +:raise_error+ Set to false to suppress ArgumentErrors on keys that
+    #   don't exist.
+    def update_attributes(values, opts = {})
+      values.each do |k, v|
+        @values[k] = Util.convert_to_stripe_object(v, opts)
+        @unsaved_values.add(k)
+      end
     end
 
     def [](k)
@@ -293,36 +310,5 @@ module Stripe
     def respond_to_missing?(symbol, include_private = false)
       @values && @values.has_key?(symbol) || super
     end
-
-    # Mass assigns attributes on the model.
-    #
-    # This is a version of +update_attributes+ that takes some extra options
-    # for internal use.
-    #
-    # ==== Options
-    #
-    # * +:opts:+ Options for StripeObject like an API key.
-    # * +:raise_error:+ Set to false to suppress ArgumentErrors on keys that
-    #   don't exist.
-    def update_attributes_with_options(values, options={})
-      # `opts` are StripeObject options
-      opts        = options.fetch(:opts, {})
-      raise_error = options.fetch(:raise_error, true)
-
-      values.each do |k, v|
-        if !@@permanent_attributes.include?(k) && !self.respond_to?(:"#{k}=")
-          if raise_error
-            raise ArgumentError,
-              "#{k} is not an attribute that can be assigned on this object"
-          else
-            next
-          end
-        end
-
-        @values[k] = Util.convert_to_stripe_object(v, opts)
-        @unsaved_values.add(k)
-      end
-      self
-    end
   end
 end

test/stripe/stripe_object_test.rb

@@ -53,10 +53,11 @@ module Stripe
       obj.update_attributes(:name => 'STRIPE')
       assert_equal "STRIPE", obj.name
 
-      e = assert_raises(ArgumentError) do
-        obj.update_attributes(:foo => 'bar')
-      end
-      assert_equal "foo is not an attribute that can be assigned on this object", e.message
+      # unfortunately, we even assign unknown properties to duplicate the
+      # behavior that we currently have via magic accessors with
+      # method_missing
+      obj.update_attributes(:unknown => 'foo')
+      assert_equal "foo", obj.unknown
     end
   end
 end