Lua test program is loaded successfully.

tests/bindings/lua/main.c

diff --git a/tests/bindings/lua/main.c b/tests/bindings/lua/main.c
index 8a30d06..379e6de 100644
--- a/tests/bindings/lua/main.c
+++ b/tests/bindings/lua/main.c
@@ -5,13 +5,19 @@
 
 #include "upb/bindings/lua/upb.h"
 
+const char *init =
+  "package.preload['lupb'] = ... "
+  "package.path = './?.lua;./third_party/lunit/?.lua'";
+
 int main() {
   int ret = 0;
   lua_State *L = luaL_newstate();
   luaL_openlibs(L);
   lua_pushcfunction(L, luaopen_lupb);
+  ret = luaL_loadstring(L, init);
+  lua_pushcfunction(L, luaopen_lupb);
 
-  if (luaL_dostring(L, "package.preload['lupb'] = ...[1]") ||
+  if (ret || lua_pcall(L, 1, LUA_MULTRET, 0) ||
       luaL_dofile(L, "tests/bindings/lua/test_upb.lua")) {
     fprintf(stderr, "error testing Lua: %s\n", lua_tostring(L, -1));
     ret = 1;