Don't add author_signature if author also is parent author

This fully completes #64

lib/diaspora_federation/entities/relayable.rb

@@ -120,7 +120,7 @@ module DiasporaFederation
       # @return [Hash] properties with updated signatures
       def enriched_properties
         super.merge(additional_data).tap do |hash|
-          hash[:author_signature] = author_signature || sign_with_author
+          hash[:author_signature] = author_signature || sign_with_author unless author == parent.root.author
         end
       end
 
@@ -129,7 +129,8 @@ module DiasporaFederation
       # @return [Hash] sorted xml elements
       def xml_elements
         data = super
-        order = signature_order + %i[author_signature]
+        order = signature_order
+        order += %i[author_signature] unless author == parent.root.author
         order.map {|element| [element, data[element].to_s] }.to_h
       end
 

spec/lib/diaspora_federation/entities/relayable_spec.rb

@@ -237,6 +237,21 @@ module DiasporaFederation
         }.to raise_error Entities::Relayable::AuthorPrivateKeyNotFound
       end
 
+      it "does not add author_signature when author is also the root author" do
+        expected_xml = <<~XML
+          <some_relayable>
+            <author>#{author}</author>
+            <guid>#{guid}</guid>
+            <parent_guid>#{parent_guid}</parent_guid>
+            <property>#{property}</property>
+          </some_relayable>
+        XML
+
+        xml = Entities::SomeRelayable.new(hash.merge(parent: Fabricate(:related_entity, author: author))).to_xml
+
+        expect(xml.to_s.strip).to eq(expected_xml.strip)
+      end
+
       it "adds 'false' booleans" do
         expected_xml = <<~XML
           <test_relayable_with_boolean>