To cite the testthat package in publications, use:

Hadley Wickham. testthat: Get Started with Testing. The R Journal, vol. 3, no. 1, pp. 5--10, 2011

As testthat is continually evolving, you may want to cite its version number. Find it with 'help(package=testthat)'.

Corresponding BibTeX entry:

  @Article{,
    author = {Hadley Wickham},
    title = {testthat: Get Started with Testing},
    journal = {The R Journal},
    year = {2011},
    volume = {3},
    pages = {5--10},
    url =
      {http://journal.r-project.org/archive/2011-1/RJournal_2011-1_Wickham.pdf},
  }