def test_function_source(self):

       def blah():

           a = 3

           b = 4

           return a + b

       descs = {'blah': blah}

       ds = DocStorage().from_dict(descs)

       t = Tracer(ds)

->     t.start_tracing()

       blah()

       t.end_tracing()

       lg = DirectPaste()

       tempdir = temppath.ensure("function_source", dir=True)

       r = RestGen(DocStorageAccessor(ds), lg, DirWriter(tempdir))

       r.write()

       assert tempdir.join("function_blah.txt").read().find("a = 3") != -1

       self.check_rest(tempdir)

       ps = DocStorageAccessor(ds)

       r = RestGen(ps, lg, DirWriter(tempdir))

       r.write()

       assert tempdir.join("function_blah.txt").read().find("a = 3") != -1

   def start_tracing(self):

       if self.tracing:

           return

       self.tracing = True

->     self.frame = py.code.Frame(sys._getframe(1))

       sys.settrace(self._tracer)