build.md
In pkgbuild: Find Tools Needed to Build R Packages

warnings can be turned into errors

Code
  build(file.path(src, "testDummy"), dest_path = dest, quiet = TRUE)
Message
  ! Stopping as requested for a warning during `R CMD build`.
  ! The full output is printed below.
  * checking for file '<file>' ... OK
  * preparing 'testDummy':
  * checking DESCRIPTION meta-information ... OK
  * checking for LF line-endings in source and make files and shell scripts
  * checking for empty or unneeded directories
    NB: this package now depends on R (>= 3.5.0)
    WARNING: Added dependency on R >= 3.5.0 because serialized objects in
    serialize/load version 3 cannot be read in older versions of R.
    File(s) containing such objects:
      'testDummy/inst/testthat-problems.rds'
  * building 'testDummy_0.1.tar.gz'

Condition
  Error in `force()`:
  ! converted from `R CMD build` warning.