diff --git a/cmd/tools/vtest-all.v b/cmd/tools/vtest-all.v
index 45c30db5ed..10b04ac6bb 100644
--- a/cmd/tools/vtest-all.v
+++ b/cmd/tools/vtest-all.v
@@ -57,6 +57,10 @@ fn get_all_commands() []Command {
 		line: '$vexe -o vtmp cmd/v'
 		okmsg: 'V can compile itself.'
 	}
+	res << Command{
+		line: '$vexe -o vtmp_werror -cflags -Werror cmd/v'
+		okmsg: 'V can compile itself with -cflags -Werror too.'
+	}
 	res << Command{
 		line: '$vexe $vargs -progress test-cleancode'
 		okmsg: 'All important .v files are invariant when processed with `v fmt`'