diff --git a/tool/test-runner.pl b/tool/test-runner.pl
index 0facdc2..7ccd801 100755
--- a/tool/test-runner.pl
+++ b/tool/test-runner.pl
@@ -23,7 +23,11 @@ my $ctx = {
     print "not " unless $success;
     print "ok - $desc\n";
     $plan++;
-  }
+  },
+  comment => sub {
+    my ($v) = @_;
+    print "# " . Minilisp::lisp_format($v) . "\n";
+  },
 };
 
 print "TAP Version 13\n";