diff --git a/test/plugin/test_in_tcp.rb b/test/plugin/test_in_tcp.rb
index 69d6bc302e..46061cb32c 100755
--- a/test/plugin/test_in_tcp.rb
+++ b/test/plugin/test_in_tcp.rb
@@ -226,8 +226,8 @@ def create_tcp_socket(host, port, &block)
 
       assert_equal 1, d.instance.log.logs.count { |l| l =~ /anonymous client/ }
       assert_equal 0, d.events.size
-
-      d.instance_shutdown
+    ensure
+      d.instance_shutdown if d&.instance
     end
   end