From: Dmitry Kurochkin <dmitry.kurochkin@gmail.com>
To: Pieter Praet <pieter@praet.org>
Subject: Re: [PATCH] test: don't bail out of `run_emacs' too early when
	missing prereqs
In-Reply-To: <87mx9qps82.fsf@praet.org>
References: <87d3aolu61.fsf@praet.org>
	<1326388619-17422-1-git-send-email-pieter@praet.org>
	<87zkdsg6ze.fsf@gmail.com> <87mx9qps82.fsf@praet.org>
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	(x86_64-pc-linux-gnu)
Date: Sun, 15 Jan 2012 17:56:37 +0400
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On Sat, 14 Jan 2012 10:07:41 +0100, Pieter Praet <pieter@praet.org> wrote:
> On Thu, 12 Jan 2012 21:34:29 +0400, Dmitry Kurochkin <dmitry.kurochkin@gmail.com> wrote:
> > On Thu, 12 Jan 2012 18:16:59 +0100, Pieter Praet <pieter@praet.org> wrote:
> > > When running the Emacs tests in verbose mode, only the first missing
> > > prereq is reported because the `run_emacs' function is short-circuited
> > > early:
> > > 
> > >   #+begin_example
> > >     emacs: Testing emacs interface
> > >      missing prerequisites: [0]  emacs(1)
> > >      skipping test: [0]  Basic notmuch-hello view in emacs
> > >      SKIP   [0]  Basic notmuch-hello view in emacs
> > >   #+end_example
> > > 
> > > This can lead to situations reminiscent of "dependency hell", so instead
> > > of returning based on each individual `test_require_external_prereq's exit
> > > status, we now do so by checking $test_subtest_missing_external_prereqs_:
> > > 
> > >   #+begin_example
> > >     emacs: Testing emacs interface
> > >      missing prerequisites: [0]  dtach(1) emacs(1) emacsclient(1)
> > >      skipping test: [0]  Basic notmuch-hello view in emacs
> > >      SKIP   [0]  Basic notmuch-hello view in emacs
> > >   #+end_example
> > > 
> > > Also add missing prereq for dtach(1).
> > > 
> > > ---
> > >  test/test-lib.sh |    6 ++++--
> > >  1 files changed, 4 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/test/test-lib.sh b/test/test-lib.sh
> > > index 82767c0..6ec3882 100644
> > > --- a/test/test-lib.sh
> > > +++ b/test/test-lib.sh
> > > @@ -907,8 +907,10 @@ EOF
> > >  
> > >  test_emacs () {
> > >  	# test dependencies beforehand to avoid the waiting loop below
> > > -	test_require_external_prereq emacs || return
> > > -	test_require_external_prereq emacsclient || return
> > > +	test_require_external_prereq dtach
> > > +	test_require_external_prereq emacs
> > > +	test_require_external_prereq emacsclient
> > > +	test -z "$test_subtest_missing_external_prereqs_" || return
> > 
> > There may be other missing dependencies before test_emacs() is called
> > and $test_subtest_missing_external_prereqs_ would not be blank.  [...]
> 
> True, hadn't though of that...
> 
> > [...] Also, I
> > would like to keep the number of functions that use
> > $test_subtest_missing_external_prereqs_ minimal.  [...]
> 
> Could you elaborate on that?
> 

This variable is supposed to be internal.  I would like to be able to
change it's meaning or replace it with something better with minimal
changes in the other code.  So I prefer it to be used only by few
"low-level" dependency functions.

This is not some strict rule, in other situation I may agree that using
$test_subtest_missing_external_prereqs_ directly is the best option.
But in this case, introducing a local variable with clean and simple
meaning is better IMO.

Regards,
  Dmitry

> > [...] How about:
> > 
> >   missing_dependencies=
> >   test_require_... dtach || missing_dependencies=1
> >   test_require_... emacs || missing_dependencies=1
> >   ...
> >   test -z "$missing_dependencies" || return
> > 
> 
> Agreed!  Patch follows.
> 
> > Regards,
> >   Dmitry
> > 
> > >  
> > >  	if [ -z "$EMACS_SERVER" ]; then
> > >  		server_name="notmuch-test-suite-$$"
> > > -- 
> > > 1.7.8.1
> > > 
> 
> 
> Peace
> 
> -- 
> Pieter