Commit 758a602

@@ -1,4 +1,4 @@
-xml.KeyDescriptor use: use do
+xml.KeyDescriptor use ? { use: use } : {} do
   xml.KeyInfo "xmlns": ::Xml::Kit::Namespaces::XMLDSIG do
     xml.X509Data do
       xml.X509Certificate stripped

@@ -106,6 +106,11 @@ module Xml
         x509.not_before
       end
 
+      def to_xml(pretty: false, xml: ::Builder::XmlMarkup.new)
+        xml = ::Xml::Kit::Template.new(self).to_xml(xml: xml)
+        pretty ? Nokogiri::XML(xml).to_xml(indent: 2) : xml
+      end
+
       class << self
         def to_x509(value)
           return value if value.is_a?(OpenSSL::X509::Certificate)

@@ -139,4 +139,21 @@ RSpec.describe Xml::Kit::Certificate do
       expect(subject.not_before).to eql(certificate.not_before)
     end
   end
+
+  describe "#to_xml" do
+    it 'generates the correct xml' do
+      result = Hash.from_xml(subject.to_xml)
+      expect(result['KeyDescriptor']).to be_present
+      expect(result['KeyDescriptor']['use']).to eql('signing')
+      expect(result['KeyDescriptor']['KeyInfo']['xmlns']).to eql(Xml::Kit::Namespaces::XMLDSIG)
+      expect(result['KeyDescriptor']['KeyInfo']['X509Data']['X509Certificate']).to eql(subject.stripped)
+    end
+
+    it 'omits the `use` when the cert can be used for both signing and encryption' do
+      subject = described_class.new(certificate, use: nil)
+      result = Hash.from_xml(subject.to_xml)
+      expect(result['KeyDescriptor']).to be_present
+      expect(result['KeyDescriptor']['use']).to be_nil
+    end
+  end
 end