diff --git a/test/webrick/test_ssl_server.rb b/test/webrick/test_ssl_server.rb
index de685bb6d3..994fde7a1b 100644
--- a/test/webrick/test_ssl_server.rb
+++ b/test/webrick/test_ssl_server.rb
@@ -13,24 +13,20 @@ class TestWEBrickSSLServer < Test::Unit::TestCase
   end
 
   def test_self_signed_cert_server
-    config = {
+    assert_self_signed_cert(
       :SSLEnable => true,
-      :SSLCertName => [["C", "JP"], ["O", "www.ruby-lang.org"], ["CN", "Ruby"]]
-    }
-    TestWEBrick.start_server(Echo, config){|server, addr, port, log|
-      sock = OpenSSL::SSL::SSLSocket.new(TCPSocket.new(addr, port))
-      sock.connect
-      sock.puts(server.ssl_context.cert.subject.to_s)
-      assert_equal("/C=JP/O=www.ruby-lang.org/CN=Ruby\n", sock.gets, log.call)
-      sock.close
-    }
+      :SSLCertName => [["C", "JP"], ["O", "www.ruby-lang.org"], ["CN", "Ruby"]],
+    )
   end
 
   def test_self_signed_cert_server_with_string
-    config = {
+    assert_self_signed_cert(
       :SSLEnable => true,
-      :SSLCertName => "/C=JP/O=www.ruby-lang.org/CN=Ruby"
-    }
+      :SSLCertName => "/C=JP/O=www.ruby-lang.org/CN=Ruby",
+    )
+  end
+
+  def assert_self_signed_cert(config)
     TestWEBrick.start_server(Echo, config){|server, addr, port, log|
       sock = OpenSSL::SSL::SSLSocket.new(TCPSocket.new(addr, port))
       sock.connect