convert string in xml_order to symbol if needed

lib/diaspora_federation/entities/relayable.rb

@@ -162,7 +162,12 @@ module DiasporaFederation
       # The order for signing
       # @return [Array]
       def signature_order
-        xml_order.nil? ? self.class::LEGACY_SIGNATURE_ORDER : xml_order.reject {|name| name =~ /signature/ }
+        if xml_order
+          prop_names = self.class.class_props.keys.map(&:to_s)
+          xml_order.reject {|name| name =~ /signature/ }.map {|name| prop_names.include?(name) ? name.to_sym : name }
+        else
+          self.class::LEGACY_SIGNATURE_ORDER
+        end
       end
 
       # @return [String] signature data string

spec/lib/diaspora_federation/entities/relayable_spec.rb

@@ -146,12 +146,7 @@ module DiasporaFederation
     end
 
     describe "#to_xml" do
-      it "adds new unknown xml elements to the xml again" do
-        hash.merge!(author_signature: "aa", parent_author_signature: "bb")
-        xml_order = [:author, :guid, :parent_guid, :property, "new_property"]
-        xml = SomeRelayable.new(hash, xml_order, "new_property" => new_property).to_xml
-
-        expected_xml = <<-XML
+      let(:expected_xml) { <<-XML }
 <some_relayable>
   <diaspora_handle>#{author}</diaspora_handle>
   <guid>#{guid}</guid>
@@ -163,6 +158,19 @@ module DiasporaFederation
 </some_relayable>
 XML
 
+      it "adds new unknown xml elements to the xml again" do
+        hash.merge!(author_signature: "aa", parent_author_signature: "bb")
+        xml_order = [:author, :guid, :parent_guid, :property, "new_property"]
+        xml = SomeRelayable.new(hash, xml_order, "new_property" => new_property).to_xml
+
+        expect(xml.to_s.strip).to eq(expected_xml.strip)
+      end
+
+      it "converts strings in xml_order to symbol if needed" do
+        hash.merge!(author_signature: "aa", parent_author_signature: "bb")
+        xml_order = %w(author guid parent_guid property new_property)
+        xml = SomeRelayable.new(hash, xml_order, "new_property" => new_property).to_xml
+
         expect(xml.to_s.strip).to eq(expected_xml.strip)
       end