Test and note for tuple types.

CHANGES.rst

@@ -13,6 +13,8 @@ Features added
 * ``PySlice_*()`` C-API functions are available from the ``cpython.slice``
   module.
 
+* Anonymous C tuple types can be declared as (ctype1, ctype2, ...).
+
 Bugs fixed
 ----------
 

tests/run/ctuple.pyx

+def convert(*o):
+    """
+    >>> convert(1, 2)
+    (1, 2.0)
+
+    >>> convert(1)
+    Traceback (most recent call last):
+    ...
+    TypeError: Expected a tuple of size 2, got tuple
+    >>> convert(1, 2, 3)
+    Traceback (most recent call last):
+    ...
+    TypeError: Expected a tuple of size 2, got tuple
+    """
+    cdef (int, double) xy = o
+    return xy
+
+cpdef (int, double) ctuple_return_type(x, y):
+    """
+    >>> ctuple_return_type(1, 2)
+    (1, 2.0)
+    """
+    return x, y