diff --git a/test/io/console/test_io_console.rb b/test/io/console/test_io_console.rb
index 342f979ec3..b5382555f5 100644
--- a/test/io/console/test_io_console.rb
+++ b/test/io/console/test_io_console.rb
@@ -395,7 +395,7 @@ defined?(PTY) and defined?(IO.console) and TestIO_Console.class_eval do
         assert_ctrl("#{cc.ord}", cc, r, w)
         assert_ctrl("#{cc.ord}", cc, r, w)
       end
-      if cc = ctrl["lnext"] && /freebsd/ !~ RUBY_PLATFORM
+      if (cc = ctrl["lnext"]) && /freebsd/ !~ RUBY_PLATFORM
         assert_ctrl("#{cc.ord}", cc, r, w)
         assert_ctrl("#{cc.ord}", cc, r, w)
         assert_ctrl("#{cc.ord}", cc, r, w)