diff --git a/module/libfib.nas b/module/libfib.nas
index d5e92f6..9df5c2c 100644
--- a/module/libfib.nas
+++ b/module/libfib.nas
@@ -19,32 +19,26 @@ var _call = dylib.limitcall(1);
 
 var _test_call = dylib.limitcall(2);
 
-
 var fib = func(x) {
     return _call(_fib, x)
 }
 
-
 var qfib = func(x) {
     return _call(_qfib, x)
 }
 
-
 var create_ghost = func() {
     return _zero_call(_create_ghost)
 }
 
-
 var set_ghost = func(object, x) {
     return _test_call(_set_ghost, object, x)
 }
 
-
 var print_ghost = func(object) {
     return _call(_print_ghost, object)
 }
 
-
 var test_ghost = func() {
     var ghost = create_ghost();
     print_ghost(nil); # err
diff --git a/test/module_test.nas b/test/module_test.nas
index 39df4f4..8c5ebdb 100644
--- a/test/module_test.nas
+++ b/test/module_test.nas
@@ -5,47 +5,7 @@ use module.libfib;
 println(keys(libfib));
 libfib.test_ghost();
 
-var libfib = func() {
-    var (dd, fib, qfib) = (nil, nil, nil);
-    var invoke = dylib.limitcall(1);
-    return {
-        open: func() {
-            if (dd==nil) {
-                dd = dylib.dlopen("libfib."~(os.platform()=="windows"?"dll":"so"));
-                fib = dd.fib;
-                qfib = dd.quick_fib;
-            } else {
-                println("[info  ] already loaded.");
-            }
-        },
-        close: func() {
-            if (dd==nil) {
-                println("[error ] already closed.");
-                return;
-            }
-            dylib.dlclose(dd.lib);
-            (dd, fib, qfib) = (nil, nil, nil);
-        },
-        fib: func(x) {
-            if (fib!=nil) {
-                return invoke(fib, x);
-            }
-            println("[error ] cannot call fib.");
-            return nil;
-        },
-        qfib: func(x) {
-            if (qfib!=nil) {
-                return invoke(qfib, x);
-            }
-            println("[error ] cannot call qfib.");
-            return nil;
-        }
-    }
-}();
-
 println("[keys  ] ", keys(libfib));
-libfib.open();
-libfib.open();
 var tm = maketimestamp();
 tm.stamp();
 println("[result] ", libfib.fib(35));
@@ -53,15 +13,19 @@ println("[time  ] ", tm.elapsedMSec()," ms");
 tm.stamp();
 println("[result] ", libfib.qfib(35));
 println("[time  ] ", tm.elapsedMSec()," ms");
-# libfib.close();
-println("[result] ", libfib.fib(35));
-println("[result] ", libfib.qfib(35));
-# libfib.close();
+println();
+
+func() {
+    for(var i = 0; i<256; i += 1) {
+        var tmp = []; # try trigger gc here to test delete ghost
+    }
+    println();
+}();
 
 var speed_test = func() {
-    var d = dylib.dlopen("libfib."~(os.platform()=="windows"? "dll":"so"));
-    println("[dylib ] ", d);
-    var fd = d.quick_fib;
+    var dd = dylib.dlopen("libfib."~(os.platform()=="windows"? "dll":"so"));
+    println("[dylib ] ", dd);
+    var fd = dd.quick_fib;
     var vec_call = dylib.dlcall;
     var invoke = dylib.limitcall(1);
     var tm = maketimestamp();