diff --git a/crates/oxide_vm/tests/define_property_descriptor_tests.rs b/crates/oxide_vm/tests/define_property_descriptor_tests.rs
index e669d4b..5278b4d 100644
--- a/crates/oxide_vm/tests/define_property_descriptor_tests.rs
+++ b/crates/oxide_vm/tests/define_property_descriptor_tests.rs
@@ -53,7 +53,8 @@ fn define_property_partial_enumerable_only_preserves_value() {
 // ── getOwnPropertyDescriptor 返回数据字段（无 get/set）──
 #[test]
 fn get_own_property_descriptor_data_fields() {
-    let r = eval_str(
+    // 返回值是数组对象，Vm 需存活到断言结束（对象值为指向会话内存的裸指针）。
+    let (_vm, r) = eval(
         "var obj={x:1}; var d=Object.getOwnPropertyDescriptor(obj,'x'); [d.value,d.writable,d.enumerable,d.configurable,d.get,d.set]",
     )
     .unwrap();
@@ -73,7 +74,8 @@ fn get_own_property_descriptor_data_fields() {
 // ── getOwnPropertyDescriptor 返回访问器字段（无 value/writable）──
 #[test]
 fn get_own_property_descriptor_accessor_fields() {
-    let r = eval_str(
+    // 返回值是数组对象，Vm 需存活到断言结束（对象值为指向会话内存的裸指针）。
+    let (_vm, r) = eval(
         "var obj={}; Object.defineProperty(obj,'x',{get:function(){return 1;},enumerable:true,configurable:true}); var d=Object.getOwnPropertyDescriptor(obj,'x'); [d.get!==undefined,d.set===undefined,d.enumerable,d.configurable,d.value===undefined,d.writable===undefined]",
     )
     .unwrap();
@@ -106,7 +108,8 @@ fn define_property_new_attributes_only_defaults_value_undefined() {
 // ── 既有属性的部分 configurable 更新保留既有值 ──
 #[test]
 fn define_property_partial_configurable_preserves_value() {
-    let r = eval_str("var obj={}; obj.x=1; Object.defineProperty(obj,'x',{configurable:false}); [obj.x]").unwrap();
+    // 返回值是数组对象，Vm 需存活到断言结束（对象值为指向会话内存的裸指针）。
+    let (_vm, r) = eval("var obj={}; obj.x=1; Object.defineProperty(obj,'x',{configurable:false}); [obj.x]").unwrap();
     let arr = unsafe { &*r.as_js_object_ptr() };
     assert!(arr.get_prop_at(0).is_int() && arr.get_prop_at(0).as_int() == 1, "value should be 1");
 }
diff --git a/crates/oxide_vm/tests/property_keys_order_tests.rs b/crates/oxide_vm/tests/property_keys_order_tests.rs
index 67c1ace..e997ea6 100644
--- a/crates/oxide_vm/tests/property_keys_order_tests.rs
+++ b/crates/oxide_vm/tests/property_keys_order_tests.rs
@@ -115,7 +115,8 @@ fn keys_with_leading_zero_not_integer_index() {
 #[test]
 fn numeric_literal_key_materializes_as_string() {
     // `{5:1}` 的键是字符串 "5"（键经 ToPropertyKey 字符串化），读 o[5]/o["5"] 同一键。
-    let r = eval_str("var o={5:1}; Object.getOwnPropertyNames(o)[0]").unwrap();
+    // 字符串值是会话内存裸指针，Vm 需存活到拷贝结束。
+    let (_vm, r) = eval("var o={5:1}; Object.getOwnPropertyNames(o)[0]").unwrap();
     assert!(r.is_string());
     let s = unsafe { &*r.as_string_ptr() }.to_owned_string();
     assert_eq!(s, "5");