diff --git a/test/open-uri/test_ssl.rb b/test/open-uri/test_ssl.rb
index 4978f93030..f653cd77ec 100644
--- a/test/open-uri/test_ssl.rb
+++ b/test/open-uri/test_ssl.rb
@@ -5,6 +5,7 @@ require 'webrick'
 begin
   require 'openssl'
   require 'webrick/https'
+  require_relative '../openssl/utils'
 rescue LoadError
 end
 require 'webrick/httpproxy'
@@ -27,6 +28,7 @@ class TestOpenURISSL
         :SSLEnable => true,
         :SSLCertificate => OpenSSL::X509::Certificate.new(SERVER_CERT),
         :SSLPrivateKey => OpenSSL::PKey::RSA.new(SERVER_KEY),
+        :SSLTmpDhCallback => proc { OpenSSL::TestUtils::TEST_KEY_DH1024 },
         :BindAddress => '127.0.0.1',
         :Port => 0})
       _, port, _, host = srv.listeners[0].addr