Make ordered expectations around results output

This also cleans up the output from the tests as previously, Base64 encoded output was printed.

lib/action/custom.rb

@@ -90,8 +90,8 @@ module Action
 
     def print_flush(str)
       return false unless str
-      print(Base64.decode64(str))
-      STDOUT.flush
+      $stdout.print(Base64.decode64(str))
+      $stdout.flush
     end
 
     def validate!

spec/action/custom_spec.rb

@@ -38,9 +38,24 @@ describe Action::Custom do
         end
 
         context 'and responds correctly' do
+          it 'prints a Base64 encoded result to $stdout' do
+            VCR.use_cassette("custom-action-ok") do
+              expect($stdout).to receive(:print).with('info_refs-result').ordered
+              expect($stdout).to receive(:print).with('push-result').ordered
+              subject.execute
+            end
+          end
+
+          context 'with results printed to $stdout' do
+            before do
+              allow($stdout).to receive(:print).with('info_refs-result')
+              allow($stdout).to receive(:print).with('push-result')
+            end
+
             it 'returns an instance of Net::HTTPCreated' do
               VCR.use_cassette("custom-action-ok") do
-              expect(subject.execute).to be_instance_of(Net::HTTPCreated)
+                expect(subject.execute ).to be_instance_of(Net::HTTPCreated)
+              end
             end
           end
         end

spec/vcr_cassettes/custom-action-ok.yml

@@ -46,7 +46,7 @@ http_interactions:
       - '1.436040'
     body:
       encoding: UTF-8
-      string: '{"result":"info_refs-result"}'
+      string: '{"result":"aW5mb19yZWZzLXJlc3VsdA==\n"}'
     http_version:
   recorded_at: Fri, 20 Jul 2018 06:18:58 GMT
 - request:
@@ -93,7 +93,7 @@ http_interactions:
       - '0.786754'
     body:
       encoding: UTF-8
-      string: '{"result":"push-result"}'
+      string: '{"result":"cHVzaC1yZXN1bHQ=\n"}'
     http_version:
   recorded_at: Fri, 20 Jul 2018 06:19:08 GMT
 recorded_with: VCR 2.4.0