diff --git a/core/libs/tests/GuestUlobjmgr.cpp b/core/libs/tests/GuestUlobjmgr.cpp
index 3f6795a979..8a04790859 100644
--- a/core/libs/tests/GuestUlobjmgr.cpp
+++ b/core/libs/tests/GuestUlobjmgr.cpp
@@ -25,4 +25,18 @@ int main() {
     Require(_sceUlobjmgrUnregisterObject(0x3fff) == 0);
     Require(_sceUlobjmgrUnregisterObject(0x4000) == einval);
     Require(_sceUlobjmgrUnregisterObject(0xffffffffu) == einval);
+
+    std::uint32_t nidId = 0xffffffffu;
+    Require(_sceUlobjmgrRegisterObject_nid_postfix(0, 1, &nidId) == einval);
+    Require(nidId == 0xffffffffu);
+    Require(_sceUlobjmgrRegisterObject_nid_postfix(0x1000, 0, &nidId) == einval);
+    Require(nidId == 0xffffffffu);
+    Require(_sceUlobjmgrRegisterObject_nid_postfix(0x1000, 1, nullptr) == einval);
+    Require(_sceUlobjmgrRegisterObject_nid_postfix(0x1000, -1, &nidId) == 0);
+    Require(nidId == 0);
+
+    Require(_sceUlobjmgrUnregisterObject_nid_postfix(nidId) == 0);
+    Require(_sceUlobjmgrUnregisterObject_nid_postfix(0x3fff) == 0);
+    Require(_sceUlobjmgrUnregisterObject_nid_postfix(0x4000) == einval);
+    Require(_sceUlobjmgrUnregisterObject_nid_postfix(0xffffffffu) == einval);
 }