test case for exception propagation across functions

tests/run/exceptionpropagation.pyx

+__doc__ = u"""
+>>> foo(0)
+>>> foo(1)
+Traceback (most recent call last):
+RuntimeError
+"""
+
+cdef int CHKERR(int ierr) except -1:
+    if ierr==0: return 0
+    raise RuntimeError
+
+cdef int obj2int(object ob) except *:
+    return ob
+
+def foo(a):
+    cdef int i = obj2int(a)
+    CHKERR(i)