Improve tests for type flags to prevent regressions

Author: ever0de

Lib/test/test_class.py

@@ -859,6 +859,7 @@ def __init__(self, arg):
 
 from _testinternalcapi import has_inline_values
 
+Py_TPFLAGS_INLINE_VALUES = (1 << 2)
 Py_TPFLAGS_MANAGED_DICT = (1 << 4)
 
 class NoManagedDict:
@@ -876,19 +877,31 @@ def __init__(self):
         self.c = 3
         self.d = 4
 
-class TestNoManagedValues(unittest.TestCase):
-    def test_flags(self):
-        self.assertEqual(NoManagedDict.__flags__ & Py_TPFLAGS_MANAGED_DICT, 0)
+class VarSizedSubclass(tuple):
+    pass
 
-    def test_no_inline_values_for_slots_class(self):
-        c = NoManagedDict()
-        self.assertFalse(has_inline_values(c))
 
 class TestInlineValues(unittest.TestCase):
 
-    def test_flags(self):
-        self.assertEqual(Plain.__flags__ & Py_TPFLAGS_MANAGED_DICT, Py_TPFLAGS_MANAGED_DICT)
-        self.assertEqual(WithAttrs.__flags__ & Py_TPFLAGS_MANAGED_DICT, Py_TPFLAGS_MANAGED_DICT)
+    def test_no_flags_for_slots_class(self):
+        flags = NoManagedDict.__flags__
+        self.assertEqual(flags & Py_TPFLAGS_MANAGED_DICT, 0)
+        self.assertEqual(flags & Py_TPFLAGS_INLINE_VALUES, 0)
+        self.assertFalse(has_inline_values(NoManagedDict()))
+
+    def test_both_flags_for_regular_class(self):
+        for cls in (Plain, WithAttrs):
+            with self.subTest(cls=cls.__name__):
+                flags = cls.__flags__
+                self.assertEqual(flags & Py_TPFLAGS_MANAGED_DICT, Py_TPFLAGS_MANAGED_DICT)
+                self.assertEqual(flags & Py_TPFLAGS_INLINE_VALUES, Py_TPFLAGS_INLINE_VALUES)
+                self.assertTrue(has_inline_values(cls()))
+
+    def test_managed_dict_only_for_varsized_subclass(self):
+        flags = VarSizedSubclass.__flags__
+        self.assertEqual(flags & Py_TPFLAGS_MANAGED_DICT, Py_TPFLAGS_MANAGED_DICT)
+        self.assertEqual(flags & Py_TPFLAGS_INLINE_VALUES, 0)
+        self.assertFalse(has_inline_values(VarSizedSubclass()))
 
     def test_has_inline_values(self):
         c = Plain()