The hardware and bandwidth for this mirror is donated by dogado GmbH, the Webhosting and Full Service-Cloud Provider. Check out our Wordpress Tutorial.
If you wish to report a bug, or if you are interested in having us mirror your free-software or open-source project, please feel free to contact us at mirror[@]dogado.de.

A whole package

2023-06-10

This vignette will teach you how to create a unit test shell for all of the examples in an entire package’s documentation.

Setup

First, let’s set up a dummy package called tempkg with just the detect.R and match.R files from the source code of the stringr package.

usethis::create_package("tempkg", open = FALSE)
#> ✔ Creating './'
#> ✔ Setting active project to '/private/var/folders/j0/sb8lpn0s4471_5sypq8qzq7h0000gn/T/Rtmpc4x6Vs/tempkg'
#> ✔ Creating 'R/'
#> ✔ Writing 'DESCRIPTION'
#> ✔ Writing 'NAMESPACE'
#> ✔ Setting active project to '/private/var/folders/j0/sb8lpn0s4471_5sypq8qzq7h0000gn/T/Rtmpc4x6Vs/tempkg'
fs::file_copy(
  system.file("extdata", c("detect.R", "match.R"), package = "exampletestr"),
  "tempkg/R/"
)

Now let’s move into the tempkg directory:

setwd("tempkg/")

and set the active project:

usethis::proj_set(".")

Main event

The detect.R file looks like this (well, I’ve abbreviated it slightly):

#' Detect the presence or absence of a pattern in a string.
#'
#' Vectorised over `string` and `pattern`.
#'
#' @param string Input vector. Either a character vector, or something
#'  coercible to one.
#' @param pattern Pattern to look for.
#'
#' @return A logical vector.
#'
#' @export
#' @examples
#' fruit <- c("apple", "banana", "pear", "pinapple")
#' str_detect(fruit, "a")
#' str_detect(fruit, "^a")
#' str_detect(fruit, "a$")
#' str_detect(fruit, "b")
#' str_detect(fruit, "[aeiou]")
str_detect <- function(string, pattern) {
  switch(type(pattern),
    empty = ,
    bound = str_count(string, pattern) > 0,
    fixed = stri_detect_fixed(string, pattern, opts_fixed = opts(pattern)),
    coll = stri_detect_coll(string, pattern, opts_collator = opts(pattern)),
    regex = stri_detect_regex(string, pattern, opts_regex = opts(pattern))
  )
}

We can make a unit tests shell file for each .R file in the package using make_tests_shells_pkg():

make_tests_shells_pkg()

This outputs test-detect.R and test-match.R files in the tests/testthat folder. As an example of what to do next, the test-detect.R file has contents

test_that("`str_detect()` works", {
  fruit <- c("apple", "banana", "pear", "pinapple")
  expect_equal(str_detect(fruit, "a"), )
  expect_equal(str_detect(fruit, "^a"), )
  expect_equal(str_detect(fruit, "a$"), )
  expect_equal(str_detect(fruit, "b"), )
  expect_equal(str_detect(fruit, "[aeiou]"), )
  expect_equal(str_detect("aecfg", letters), )
})

which can be sensibly completed as

test_that("`str_detect()` works", {
  fruit <- c("apple", "banana", "pear", "pinapple")
  expect_equal(str_detect(fruit, "a"), rep(TRUE, 4))
  expect_equal(str_detect(fruit, "^a"), c(TRUE, rep(FALSE, 3)))
  expect_equal(str_detect(fruit, "a$"), c(FALSE, TRUE, FALSE, FALSE))
  expect_equal(str_detect(fruit, "b"), c(FALSE, TRUE, FALSE, FALSE))
  expect_equal(str_detect(fruit, "[aeiou]"), rep(TRUE, 4))
  expect_equal(
    str_detect("aecfg", letters),
    letters %in% c("a", "c", "e", "f", "g")
  )
})

test-match.R must similarly be completed.

Cleanup

knitr::opts_knit$set(root.dir = tempdir(check = TRUE))
if (fs::dir_exists("tempkg")) fs::dir_delete("tempkg")
knitr::opts_knit$set(root.dir = init_wd)

These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.
Health stats visible at Monitor.