Re: [PATCH] tests: use the get_shell_script helper function

[Stefano Lattarini]

On 03/01/2012 09:28 AM, Peter Rosin wrote:
> tests/libobj-basic.test: Use the get_shell_script convenience
> function instead of doing an inferior local hack.
> tests/libobj10.test: Likewise.
> tests/libobj19.test: Likewise.
> tests/pr401.test: Likewise.
> tests/pr401b.test: Likewise.
> tests/pr401c.test: Likewise.
> ---
>  tests/libobj-basic.test |    2 +-
>  tests/libobj10.test     |    2 +-
>  tests/libobj19.test     |    4 ++--
>  tests/pr401.test        |    2 +-
>  tests/pr401b.test       |    2 +-
>  tests/pr401c.test       |    2 +-
>  6 files changed, 7 insertions(+), 7 deletions(-)
> 
> Hi!
> 
> I happened to notice get_shell_script in some test, and am thus
> proposing this patch.  Ok for master?
>
No, sorry.  The patch is based on a misunderstanding.  The 'get_shell_script'
is not meant to just fetch an automake-provided script to be tested -- it has
other implications:

  * When the variable '$am_test_prefer_config_shell' is set to "yes", the
    'get_shell_script' function tweaks the fetched script so that it uses
    the configure-time determined '$SHELL' rather than bare '/bin/sh' in
    its shebang line.

  * If a test case uses 'get_shell_script', the 'gen-testsuite-part'
    script automatically generates a sibling tests for it that defines
    '$am_test_prefer_config_shell' to "yes", so that the fetched script
    will be "transparently" tested also with /bin/sh.

The first effect is useless if the script in only invoked from the
Makefile rules (since there it should already be run by $(SHELL)), and
the second effect is actually harmful, since it causes the creation of
a sibling script which is semantically 100% identical to the original
one (like our testsuite needs to be slowed even more !).

But your misunderstanding shows that the 'get_shell_script' name is
indeed poorly chosen, and confusing.  We should improve it -- maybe
rename it to 'get_cooked_shell_script'?  And probably, now that I think
about it, the explanation I've given above about the interaction with
'gen-testsuite-part' should be written down explicitly in the comments
for 'get_shell_script' (and a similar explanation should be written
for the 'fetch_tap_driver' function).  I will do this in the weekend,
unless someone wants to win extra kudos and beat me at it.

(And then, we could also define a new 'get_am_script' function that
merely fetches the given automake-provided script verbatim from the
proper directory -- at which point your patch could be resurrected
with minor tweakings).

Thanks,
  Stefano