Testing R Packages with testthat

Modern best practices for R package testing using testthat 3+.

Initial Setup

Initialize testing with testthat 3rd edition:

usethis::use_testthat(3)

This creates tests/testthat/ directory, adds testthat to DESCRIPTION Suggests with Config/testthat/edition: 3, and creates tests/testthat.R.

File Organization

Mirror package structure:

• Code in R/foofy.R → tests in tests/testthat/test-foofy.R
• Use usethis::use_r("foofy") and usethis::use_test("foofy") to create paired files