test(inspec): check that apt-cacher-ng port is opened

test/integration/default/controls/service_spec.rb

@@ -8,5 +8,8 @@ control 'AptCacherNG service' do
 
   describe port(9999) do
     it { should be_listening }
+    its('processes') { should include 'apt-cacher-ng' }
+    its('protocols') { should include 'tcp' }
+    its('addresses') { should include '0.0.0.0' }
   end
 end