[Rd] beginner's guide to C++ programming with R packages?

[Ross Boylan]

On Fri, 2009-06-26 at 16:17 -0400, Whit Armstrong wrote:
> > But this draws me back to the basic question.  I don't want to run R
> > CMD INSTALL 20 times per hour.  How do developers "actually" test
> > their code?
> 
> check out RUnit for tests.
> http://cran.r-project.org/web/packages/RUnit/index.html
> 
> as for testing c++ code.  I have taken an approach which is probably
> different than most.  I try to build my package as a c++ library that
> can be used independent of R.  Then you can test your library with
> whatever c++ test suite that you prefer.  Once you are happy, then
I also have C++ tests that operate separately from R, though I have a
very small library of stub R functions to get the thing to build.  There
have been some tricky issues with R (if one links to the regular R
library) and the test framework fighting over who was "main."  I think
that's why I switched to the stub.

Working only with R level tests alone does not permit the kind of lower
level testing that you can get by running your own unit tests.  I use
the boost unit test framework.

Of course, you want R level tests too.  Some of my upper level C++ tests
are mirror images of R tests; this can help identify if a problem lies
at the interface.

For C++ tests I build my code in conjunction with a main program.

I think I also have or had a test building it as a library, but I don't
use that much.

For R, my modules get built into a library.

It's usually cleaner to build the R library from a fresh version of the
sources; otherwise scraps of my other builds tend to end up in the R
package.

Thanks, Whit, for the  pointers to Rcpp and RAbstraction.
Ross Boylan