diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py
index efa9459a58629d..64c74ec2c59ae0 100644
--- a/Lib/test/test_builtin.py
+++ b/Lib/test/test_builtin.py
@@ -737,11 +737,6 @@ def test_exec_globals(self):
         self.assertRaises(TypeError,
                           exec, code, {'__builtins__': 123})
 
-        # no __build_class__ function
-        code = compile("class A: pass", "", "exec")
-        self.assertRaisesRegex(NameError, "__build_class__ not found",
-                               exec, code, {'__builtins__': {}})
-
         class frozendict_error(Exception):
             pass
 
@@ -758,6 +753,15 @@ def __setitem__(self, key, value):
         self.assertRaises(frozendict_error,
                           exec, code, {'__builtins__': frozen_builtins})
 
+        # no __build_class__ function
+        code = compile("class A: pass", "", "exec")
+        self.assertRaisesRegex(NameError, "__build_class__ not found",
+                               exec, code, {'__builtins__': {}})
+        # __build_class__ in a custom __builtins__
+        exec(code, {'__builtins__': frozen_builtins})
+        self.assertRaisesRegex(NameError, "__build_class__ not found",
+                               exec, code, {'__builtins__': frozendict()})
+
         # read-only globals
         namespace = frozendict({})
         code = compile("x=1", "test", "exec")