rewrite test to @isolation.runInSubprocess()

Author: deadlovelll

Lib/test/test_class.py

@@ -1113,34 +1113,30 @@ def test_prepare_preserves_order(self):
 
 
     @support.nomemtest
+    @isolation.runInSubprocess()
     def test_clear_managed_dict_no_memory_keeps_exception(self):
         # gh-152083: an exception may already be set when the managed dict is
-        # cleared under low memory. PyErr_FormatUnraisable() must not clear it.
-        code = """if 1:
-            import _testcapi
-
-            class A:
-                def __init__(self):
-                    self.a = 1
-                    self.b = 2
-
-            def f():
-                a = A()
-                a.__dict__
-                return [None] * 1000
-
-            for start in range(120):
-                _testcapi.set_nomemory(start)
-                try:
-                    f()
-                except BaseException:
-                    pass
-            _testcapi.remove_mem_hooks()
-        """
-        rc, out, err = script_helper.assert_python_ok("-c", code)
-        self.assertEqual(rc, 0)
-        self.assertFalse(out, msg=out.decode('utf-8'))
-        self.assertFalse(err, msg=err.decode('utf-8'))
+        # cleared under low memory.  PyErr_FormatUnraisable() must not clear it.
+        import _testcapi
+
+        class A:
+            def __init__(self):
+                self.a = 1
+                self.b = 2
+
+        def f():
+            a = A()
+            a.__dict__
+            return [None] * 1000
+
+        for start in range(120):
+            _testcapi.set_nomemory(start)
+            try:
+                f()
+            except BaseException:
+                pass
+        _testcapi.remove_mem_hooks()
+
 
 if __name__ == '__main__':
     unittest.main()