use_r: Create or edit R or test files

In usethis: Automate Package and Project Setup

Create or edit R or test files

Description

This pair of functions makes it easy to create paired R and test files, using the convention that the tests for R/foofy.R should live in tests/testthat/test-foofy.R. You can use them to create new files from scratch by supplying name, or if you use RStudio, you can call to create (or navigate to) the companion file based on the currently open file. This also works when a test snapshot file is active, i.e. if you're looking at ⁠tests/testthat/_snaps/foofy.md⁠, use_r() or use_test() take you to R/foofy.R or tests/testthat/test-foofy.R, respectively.

Usage

use_r(name = NULL, open = rlang::is_interactive())

use_test(name = NULL, open = rlang::is_interactive())

Arguments

name	Either a string giving a file name (without directory) or NULL to take the name from the currently open file in RStudio.
open	Whether to open the file for interactive editing.

Renaming files in an existing package

Here are some tips on aligning file names across ⁠R/⁠ and ⁠tests/testthat/⁠ in an existing package that did not necessarily follow this convention before.

This script generates a data frame of ⁠R/⁠ and test files that can help you identify missed opportunities for pairing:

library(fs)
library(tidyverse)

bind_rows(
  tibble(
    type = "R",
    path = dir_ls("R/", regexp = "\\.[Rr]$"),
    name = as.character(path_ext_remove(path_file(path))),
  ),
  tibble(
    type = "test",
    path = dir_ls("tests/testthat/", regexp = "/test[^/]+\\.[Rr]$"),
    name = as.character(path_ext_remove(str_remove(path_file(path), "^test[-_]"))),
  )
) |>
  pivot_wider(names_from = type, values_from = path) |>
  print(n = Inf)

The rename_files() function can also be helpful.

See Also

• The testing and R code chapters of R Packages.

• use_test_helper() to create a testthat helper file.

Examples

## Not run: 
# create a new .R file below R/
use_r("coolstuff")

# if `R/coolstuff.R` is active in a supported IDE, you can now do:
use_test()

# if `tests/testthat/test-coolstuff.R` is active in a supported IDE, you can
# return to `R/coolstuff.R` with:
use_r()

## End(Not run)

usethis documentation built on Sept. 9, 2025, 5:25 p.m.