support :order! key with value :schema_order

lib/savon/qualified_message.rb

@@ -14,7 +14,13 @@ def to_hash(hash, path)
       return hash.map { |value| to_hash(value, path) } if hash.is_a?(Array)
       return hash.to_s unless hash.is_a?(Hash)
 
-      hash.each_with_object({}) do |(key, value), newhash|
+      if hash[:order!] == :use_schema || @order_with_schema
+        @order_with_schema = true
+        ordered_keys = @used_namespaces.select { |t| t.first == path.first && t.length == 2 }.keys.collect { |k| k.last }
+        hash[:order!] = ordered_keys
+      end
+
+      result = hash.each_with_object({}) do |(key, value), newhash|
         case key
         when :order!
           newhash[key] = add_namespaces_to_values(value, path)
@@ -32,6 +38,8 @@ def to_hash(hash, path)
         end
         newhash
       end
+
+      ordered_keys(result)
     end
 
     private
@@ -48,5 +56,15 @@ def add_namespaces_to_values(values, path)
         namespace.empty? ? value : "#{namespace}:#{translated_value}"
       end
     end
+
+    def ordered_keys(hash)
+      return hash unless @order_with_schema
+
+      if order_keys = hash.delete(:order!)
+        present_order_keys = order_keys & hash.keys
+        hash[:order!] = (present_order_keys + (hash.keys - present_order_keys)).select { |key| !key.to_s.end_with?('!') }
+      end
+      hash
+    end
   end
 end

spec/savon/qualified_message_spec.rb

@@ -64,6 +64,35 @@ module Savon
         expect(xml).to eq good_xml
       end
 
+      it "uses schema order when :order! is set to :use_schema" do
+        used_namespaces = {
+          %w(tns Foo) => 'ns'
+        }
+
+        hash = {
+          :foo => {
+            :order! => :use_schema,
+            :bar => 'zing',
+            :cash => 'pow'
+          }
+        }
+
+        good_result = {
+          "ns:Foo" => {
+            :order! => [:bar, :cash],
+            :bar => 'zing',
+            :cash => 'pow'
+          }
+        }
+
+        message = described_class.new(types, used_namespaces, key_converter)
+        resulting_hash = message.to_hash(hash, ['tns'])
+
+        expect(Gyoku.xml(resulting_hash, key_converter: key_converter)).to eq %(<ns:Foo><Bar>zing</Bar><Cash>pow</Cash></ns:Foo>)
+        expect(resulting_hash).to eq good_result
+
+      end
+
       it "properly handles boolean false" do
         used_namespaces = {
           %w(tns Foo) => 'ns'