Tests for tp_dictoffset

test/test_extension/slots_test.c

 #include <Python.h>
+#include <stddef.h> /* For offsetof */
 
 typedef struct {
-    PyObject_HEAD
+    PyObject_HEAD;
+
+    PyObject* dict;
 
     int n;
 } slots_tester_object;
@@ -252,7 +255,7 @@ static PyTypeObject slots_tester_map= {
     0,                                  /* tp_dict */
     0,                                  /* tp_descr_get */
     0,                                  /* tp_descr_set */
-    0,                                  /* tp_dictoffset */
+    offsetof(slots_tester_object, dict), /* tp_dictoffset */
     0,                                  /* tp_init */
     0,                                  /* tp_alloc */
     slots_tester_new,                   /* tp_new */

test/tests/capi_slots.py

@@ -88,3 +88,27 @@ try:
         pass
 except TypeError, e:
     print e
+
+try:
+    slots_test.SlotsTesterSeq(5).foo = 1
+except AttributeError, e:
+    print e
+
+try:
+    print slots_test.SlotsTesterSeq(5).__dict__
+except AttributeError, e:
+    print e
+
+c = C3(5)
+c.foo = 1
+print c.foo
+print c.__dict__
+
+s = slots_test.SlotsTesterMap(6)
+s.bar = 2
+print s.bar
+print hasattr(s, "bar"), hasattr(s, "foo")
+try:
+    print s.__dict__
+except AttributeError, e:
+    print e