[R-pkg-devel] CRAN packages suggesting other packages but not using them conditionally

[Duncan Murdoch]

On 12/12/2020 6:01 p.m., Ben Bolker wrote:
> 
> 
> On 12/12/20 5:50 PM, Duncan Murdoch wrote:
>> On 12/12/2020 4:08 p.m., Spencer Graves wrote:
>>> Hi, Ben et al.:
>>>
>>>
>>> On 2020-12-12 13:43, Ben Bolker wrote:
>>>>      Apologies if I'm telling you something you already know:
>>>>
>>>>      By default, fda::CRAN() uses the presence of environment variables
>>>> matched by the regexp "^_R_" as a heuristic to decide whether it's being
>>>> running on CRAN.
>>>>
>>>>      testthat::skip_on_cran()  calls testthat::on_cran() to look for an
>>>> environment variable called NOT_CRAN equal to "true". The
>>>> devtools::check() machinery automatically sets this variable.
>>>
>>>
>>>    > testthat::on_cran
>>> Error: 'on_cran' is not an exported object from 'namespace:testthat'
>>>
>>>
>>>        Besides, on my Mac, I get:
>>>
>>>
>>>    > testthat:::on_cran()
>>> [1] TRUE
>>>
>>>
>>>        My Mac is NOT CRAN, and I don't want that function to return
>>> TRUE on
>>> my computer unless I explicitly run "R CMD check --on-cran".
>>>
>>>
>>>>      So: fda::CRAN() depends on breakable assumptions, defaults to FALSE
>>>> in an empty environment.  skip_on_cran() defaults to TRUE in an empty
>>>> environment (but defaults to FALSE in a devtools::check() environment).
>>>
>>>        If future changes break fda::CRAN, I will have to deal with it
>>> then.
>>>
>>>
>>>        I'd be happier if the CRAN maintainers would develop a procedure to
>>> make it easier for package maintainers do two things:
>>>
>>>
>>>              * Include tests in their package that run longer than the
>>> time
>>> limit permitted on CRAN.
>>
>> That's very easy now.  Just put them in a "slowtests" directory, and
>> tell R CMD check to use that.  How could it be easier?
> 
>      How would you do that?  In "R CMD check --help" I see that one can
> use --test-dir= to specify the test directory, but I don't see a way to
> specify _additional_ test directories; short of setting a tests/
> directory with CRAN-specific tests and a slowtests/ directory with
> *both* CRAN-specific and CRAN-excluded tests (thus duplicating files,
> which seems clunky), I don't see how to do this within a standard R CMD
> check framework (without testing a CRAN-indicating environment variable,
> which gets us back where we started ...)  Or would you run R CMD check
> twice, once without and once with --test-dir=slowtests ?

What I would do is have the slowtests run the regular tests.  So if I 
want both, I run slowtests.  If I want just the fast ones, I don't 
specify.  I can't think why I wouldn't want to run the slow ones without 
the fast ones, but if I did, it's not too hard to figure out a scheme 
that runs fast by default, slow when requested, and both if you request 
that instead.

> 
>     There doesn't seem to be very much in "Writing R Extensions" about
> testing - a little bit in
> https://cran.r-project.org/doc/manuals/r-release/R-exts.html#Package-subdirectories
> 
>     What am I missing?
> 
>    Just to clarify, the ideal would be to be able to designate a separate
> set of tests that were *not* run on CRAN, and to be able to run them in
> the same "R CMD check" pass as the CRAN-specific tests.  

Yes, do that as described above.

There are a
> bunch of ways to achieve this, but I think Spencer is saying (and I
> agree) that it would be nice if it were there an official mechanism that
> made this easier (and it seems pretty easy if the CRAN maintainers were
> agreeable to the idea ...

There is such a mechanism, and I've just described it (and not for the 
first time; it's also described in WRE).  I think the problem is that 
you and Spencer are looking for something that's more complicated.  It 
doesn't need to be complicated.

Duncan Murdoch