extended test case, includes attribute access testing

tests/run/closure_self.pyx

+cdef class Test:
+    cdef int x
+
 cdef class SelfInClosure(object):
+    cdef Test _t
+    cdef int x
+
+    def plain(self):
         """
         >>> o = SelfInClosure()
-    >>> o.closure_method()() == o
-    True
+        >>> o.plain()
+        1
         """
+        self.x = 1
+        return self.x
 
     def closure_method(self):
+        """
+        >>> o = SelfInClosure()
+        >>> o.closure_method()() == o
+        True
+        """
         def nested():
             return self
         return nested
+
+    def closure_method_cdef_attr(self, Test t):
+        """
+        >>> o = SelfInClosure()
+        >>> o.closure_method_cdef_attr(Test())()
+        (1, 2)
+        """
+        t.x = 2
+        self._t = t
+        self.x = 1
+        def nested():
+            return self.x, t.x
+        return nested