diff --git a/tests/lua/n6.lua b/tests/lua/n6.lua
index 145013231..5aabdb08d 100644
--- a/tests/lua/n6.lua
+++ b/tests/lua/n6.lua
@@ -1,5 +1,8 @@
-assert(name("a", "b"):append_after(1) == name("a", "b1"))
-assert(name("a", 1):append_after(2) == name("a", 1, "2"))
+assert(name("a", "b"):append_after(1) == name("a", "b_1"))
+assert(name("a", 1):append_after(2) == name("a", 1, "_2"))
 assert(name("a", "b"):append_after("k") == name("a", "bk"))
 assert(name("a", "b"):append_before("k") == name("a", "kb"))
 assert(name("a", 1):append_before("k") == name("a", "k", 1))
+assert(name():append_after("a") == name("a"))
+assert(name():append_after(1) == name("_1"))
+assert(name():append_before("b") == name("b"))