diff --git a/manifests/init.pp b/manifests/init.pp
index 653a090..72ff506 100644
--- a/manifests/init.pp
+++ b/manifests/init.pp
@@ -30,6 +30,7 @@
   if $manage_user {
     user { $user:
       gid        => $group,
+      system     => true,
       managehome => true,
     }
   }
@@ -37,6 +38,7 @@
   if $manage_group {
     group { $group:
       ensure => present,
+      system => true,
     }
   }
 
diff --git a/spec/unit/classes/selenium_spec.rb b/spec/unit/classes/selenium_spec.rb
index b27b182..03c79f0 100644
--- a/spec/unit/classes/selenium_spec.rb
+++ b/spec/unit/classes/selenium_spec.rb
@@ -26,8 +26,14 @@
     path_version = p[:version].match(/^(\d+\.\d+)\./)[1]
 
     it do
-      should contain_user(p[:user]).with_gid(p[:group])
-      should contain_group(p[:group])
+      should contain_user(p[:user]).with(
+        :gid        => p[:group],
+        :system     => true,
+        :managehome => true
+      )
+      should contain_group(p[:group]).with(
+        :system => true
+      )
       should contain_class('wget')
       should contain_class('selenium').with_version(p[:version])
       should contain_file("#{p[:install_root]}").with({