diff --git a/t/test-lib.sh b/t/test-lib.sh
index 562c57e685..f6318c54c9 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -379,6 +379,7 @@ unset VISUAL EMAIL LANGUAGE COLUMNS $("$PERL_PATH" -e '
 	my @env = keys %ENV;
 	my $ok = join("|", qw(
 		TRACE
+		TR2_
 		DEBUG
 		TEST
 		.*_TEST