diff --git a/Lib/test/test_capi.py b/Lib/test/test_capi.py
index 72c648f54d8b70a..39b1b646511638b 100644
--- a/Lib/test/test_capi.py
+++ b/Lib/test/test_capi.py
@@ -839,7 +839,11 @@ def check_pyobject_is_freed(self, func_name):
             except _testcapi.error:
                 os._exit(1)
         ''')
-        assert_python_ok('-c', code, PYTHONMALLOC=self.PYTHONMALLOC)
+        assert_python_ok(
+            '-c', code,
+            PYTHONMALLOC=self.PYTHONMALLOC,
+            MALLOC_CONF="junk:false",
+        )
 
     def test_pyobject_null_is_freed(self):
         self.check_pyobject_is_freed('check_pyobject_null_is_freed')