Re: [gnugo-devel] using problems for regression tests

[Gunnar Farneback]

Evan wrote:
> I was wondering what our policy is on using problems from books for
> regression testing.

To begin with there is absolutely no problem *using* problems from
books for testing the engine. The problem comes with *distributing*
them. Of course the latter is usually critical for our purposes but
it's important to be aware of the distinction.

> I notice we have some problems from Get Strong at the
> Endgame; would finding problems Gnu Go has trouble with and entering them
> in be considered generally acceptable, or are things more complicated than
> that?

Things are a lot more complicated than that. Without being an expert
on copyright law (which to some extent also varies between countries),
I consider the following cases safe enough:

* Problems taken directly from sufficiently old sources are okay.
  Exactly what sufficiently old means is somewhat difficult to say,
  however. Currently Swedish law says that copyright protection ends
  when the author has been dead for 70 years. I believe that the
  situation is similar also in other parts of the world, including a
  disturbing trend that the length of protection is extended (it used
  to be 50 years in Sweden) any time "Mein Kampf" or Mickey Mouse gets
  close to slipping into the public domain.

* The *ideas* in general and common problems can be used. For
  example most of the test cases in ld_owl.tst are common life and
  death problems which occur in lots of life and death books as well
  as in real games. Compared to the books the configuration of
  surrounding stones is different (no go book author would ever
  consider using such an artificial position). However, there is still
  the matter of potential copyright on the selection of problems,
  etc., so one shouldn't organize the problems in the same way.
  The commenting text in books is of course off limits but not
  interesting for our purposes anyway.

* Problems from books where the author (or more generally copyright
  owner) has given explicit permission.

* Unusual or complex problems had better be avoided. However, there
  are some fair use provisions that may be invoked to include sample
  problems verbatim from other sources. Still we shouldn't rely on
  this too much.

/Gunnar