Thank you!
That's a handy technique and it does help.
As I understand, there's no way to extend that to multiple lines?
One-liners for tests are enough sometimes, but not always.
For those cases, it is cumbersome to split as well.

пн, 22 апр. 2019 г. в 22:51, Berry, Charles <ccberry@ucsd.edu>:

> It looks like you want the :epilogue header argument. See inline.
>
> > On Apr 22, 2019, at 2:00 AM, Dmitrii Korobeinikov <dim1212k@gmail.com>
> wrote:
> >
> > When I write several source blocks, which depend on one another, I tend
> to debug them one by one.
> >
> > So, I write this function and test it:
> >
> > #+NAME: square
> > #+BEGIN_SRC python
> >     square = lambda x: x * x
> >     return square(5)
> > #+END_SRC
> >
> > #+RESULTS: square
> > : 25
> >
>
>
> Equivalently, you could run this:
>
> #+NAME: square
> #+BEGIN_SRC python :epilogue  return square(5)
>     square = lambda x: x * x
> #+END_SRC
>
>
>
> > After I see that the test is successful, I write this client function:
> >
> > #+BEGIN_SRC python :noweb yes
> >     <<square>>
> >     return 5 + square(5)
> > #+END_SRC
> >
> > #+RESULTS:
> > : 25
> >
> > And here, to get the correct result, I have to remove the ~return
> square(5)~ line in ~<<square>>~.
> > But I don't want to lose testing!
> > S
>
> With my version of `square`, the epilogue is not included.
>
> So it works as you want it to.
>
> HTH,
>
> Chuck
>
>
>