Package dependencies for R CMD check

Question

The DESCRIPTION file in R packages has several ways of specifying dependencies, eg Depends , Suggests and Imports . Which one should I use to specify a dependency that is optional once the package is installed, but required for running R CMD check ?

In my particular case I am using testthat to run some tests automatically when R CMD check is run, but during "normal" operation, testthat is not required. The answer to this question suggests that testthat should be in Suggests , but is that enough to ensure that R CMD check runs correctly?

What I would like to see, if it exists, is a field where I can speciy dependencies that are required only to run R CMD check , which should fail with an appropriate error message if these packages are not available.

Answer 1

Yes, you should put them in the Suggests field. The only other thing required for R CMD check to run successfully is to ensure the packages in the Suggests field are installed in a location that will be found by R CMD check .

If they're not available, you can set the environment variable _R_CHECK_FORCE_SUGGESTS=false and R CMD check will run, with a "NOTE" about the missing suggested packages.