Commit 3572105

@@ -23,9 +23,9 @@ module Saml
           saml_document.query_string_parameter => Content.encode_raw_saml(saml_document.to_xml),
           'RelayState' => relay_state,
           'SigAlg' => Saml::Kit::Namespaces::SHA256,
-        }.map do |(x, y)|
-          "#{x}=#{y}"
-        end.join('&')
+        }.map do |(key, value)|
+          value.present? ?  "#{key}=#{value}" : nil
+        end.compact.join('&')
         payload = URI.encode(payload)
       end
     end

@@ -41,6 +41,11 @@ RSpec.describe Saml::Kit::UrlBuilder do
           expect(result).to include("RelayState=#{URI.encode(relay_state)}")
         end
 
+        it 'excludes the relay state' do
+          query_params = to_query_params(subject.build(response))
+          expect(query_params['RelayState']).to be_nil
+        end
+
         it 'includes a signature' do
           result = subject.build(response, relay_state: relay_state)
           query_params = to_query_params(result)
@@ -52,6 +57,17 @@ RSpec.describe Saml::Kit::UrlBuilder do
           expected_signature = Base64.strict_encode64(Saml::Kit.configuration.signing_private_key.sign(OpenSSL::Digest::SHA256.new, payload))
           expect(query_params['Signature']).to eql(expected_signature)
         end
+
+        it 'generates the signature correctly when the relay state is absent' do
+          result = subject.build(response)
+          query_params = to_query_params(result)
+          expect(query_params['SigAlg']).to eql(URI.encode(Saml::Kit::Namespaces::SHA256))
+
+          payload = "#{query_string_parameter}=#{query_params[query_string_parameter]}"
+          payload << "&SigAlg=#{query_params['SigAlg']}"
+          expected_signature = Base64.strict_encode64(Saml::Kit.configuration.signing_private_key.sign(OpenSSL::Digest::SHA256.new, payload))
+          expect(query_params['Signature']).to eql(expected_signature)
+        end
       end
     end
   end