diff --git a/Rakefile b/Rakefile
index a99e97f..c43d774 100644
--- a/Rakefile
+++ b/Rakefile
@@ -8,6 +8,7 @@ Hoe.spec 'pg-ldap-sync' do
 
   extra_deps << ['net-ldap', '>= 0.2']
   extra_deps << ['kwalify', '>= 0.7']
+  extra_dev_deps << ['ruby-ldapserver', '>= 0.3']
 
   self.readme_file = 'README.rdoc'
   spec_extras[:rdoc_options] = ['--main', readme_file, "--charset=UTF-8"]