diff --git a/body_chunked.t b/body_chunked.t
index 181fca6..32903f4 100644
--- a/body_chunked.t
+++ b/body_chunked.t
@@ -22,7 +22,7 @@
 select STDERR; $| = 1;
 select STDOUT; $| = 1;
 
-my $t = Test::Nginx->new()->has(qw/http proxy rewrite/)->plan(11);
+my $t = Test::Nginx->new()->has(qw/http proxy rewrite/)->plan(13);
 
 $t->write_file_expand('nginx.conf', <<'EOF');
 
@@ -134,6 +134,39 @@
 	'0123456789', 'foobar'), qr/(TEST.*){4}/ms,
 	'chunked body discard 2');
 
+# invalid chunks
+
+TODO: {
+local $TODO = 'not yet' unless $t->has_version('1.17.4');
+
+like(
+	http(
+		'GET / HTTP/1.1' . CRLF
+		. 'Host: localhost' . CRLF
+		. 'Connection: close' . CRLF
+		. 'Transfer-Encoding: chunked' . CRLF . CRLF
+		. '4' . CRLF
+		. 'SEE-THIS' . CRLF
+		. '0' . CRLF . CRLF
+	),
+	qr/400 Bad/, 'runaway chunk'
+);
+
+unlike(
+	http(
+		'GET /discard HTTP/1.1' . CRLF
+		. 'Host: localhost' . CRLF
+		. 'Connection: close' . CRLF
+		. 'Transfer-Encoding: chunked' . CRLF . CRLF
+		. '4' . CRLF
+		. 'SEE-THIS' . CRLF
+		. '0' . CRLF . CRLF
+	),
+	qr/200 OK/, 'runaway chunk discard'
+);
+
+}
+
 # proxy_next_upstream
 
 like(http_get_body('/next', '0123456789'),