diff --git a/test/api/test-buffer.c b/test/api/test-buffer.c
index 13465ef8d..0b70cf968 100644
--- a/test/api/test-buffer.c
+++ b/test/api/test-buffer.c
@@ -704,6 +704,7 @@ static const utf16_conversion_test_t utf16_conversion_tests[] = {
   {{0x41, 0xD800, 0xDF02}, {-1}},
   {{0x41, 0x61, 0xD800, 0xDF02}, {0x61, -1}},
   {{0x41, 0xD800, 0x61, 0xDF02}, {-1, 0x61}},
+  {{0x41, 0xDF00, 0x61}, {-1}},
   {{0x41, 0x61}, {0}}
 };