testthat: local_test_context – R documentation

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local_test_context

Locally set options for maximal test reproducibility

Description

local_test_context() is run automatically by test_that() but you may want to run it yourself if you want to replicate test results interactively. If run inside a function, the effects are automatically reversed when the function exits; if running in the global environment, use withr::deferred_run() to undo.

local_reproducible_output() is run automatically by test_that() in the 3rd edition. You might want to call it to override the the default settings inside a test, if you want to test Unicode, coloured output, or a non-standard width.

Usage

local_test_context(.env = parent.frame())

local_reproducible_output(
  width = 80,
  crayon = FALSE,
  unicode = FALSE,
  .env = parent.frame()
)

Arguments

`.env`	Environment to use for scoping; expert use only.
`width`	Value of the `"width"` option.
`crayon`	Value of the `"crayon.enabled"` option.
`unicode`	Value of the `"cli.unicode"` option. The test is skipped if l10n_info()$`UTF-8` is `FALSE`.

Details

local_test_context() sets TESTTHAT = "true", which ensures that is_testing() returns TRUE and allows code to tell if it is run by testthat.

In the third edition, local_test_context() also calls local_reproducible_output() which temporary sets the following options:

cli.dynamic = FALSE so that tests assume that they are not run in a dynamic console (i.e. one where you can move the cursor around).
cli.unicode (default: FALSE) so that the cli package never generates unicode output (normally cli uses unicode on Linux/Mac but not Windows). Windows can't easily save unicode output to disk, so it must be set to false for consistency.
crayon.enabled (default: FALSE) suppresses ANSI colours generated by the crayon package (normally colours are used if crayon detects that you're in a terminal that supports colour).
lifecycle_verbosity = "warning" so that every lifecycle problem always generates a warning (otherwise deprecated functions don't generate a warning every time).
OutDec = "." so numbers always uses . as the decimal point (European users sometimes set OutDec = ",").
rlang_interactive = FALSE so that rlang::is_interactive() returns FALSE, and code that uses it pretends you're in a non-interactive environment.
useFancyQuotes = FALSE so base R functions always use regular (straight) quotes (otherwise the default is locale dependent, see sQuote() for details).
width (default: 80) to control the width of printed output (usually this varies with the size of your console).

And modifies the following env vars:

Unsets RSTUDIO, which ensures that RStudio is never detected as running.
Sets LANGUAGE = "en", which ensures that no message translation occurs.

Finally, it sets the collation locale to "C", which ensures that character sorting the same regardless of system locale.

Examples

local({
  local_test_context()
  cat(crayon::blue("Text will not be colored"))
  cat(cli::symbol$ellipsis)
  cat("\n")
})

ellipsis <- cli::symbol$ellipsis
test_that("test ellipsis", {
  expect_equal(ellipsis, cli::symbol$ellipsis)

  local_reproducible_output(unicode = TRUE)
  expect_equal(ellipsis, cli::symbol$ellipsis)
})

testthat

Unit Testing for R

v3.0.2

MIT + file LICENSE

Authors

Hadley Wickham [aut, cre], RStudio [cph, fnd], R Core team [ctb] (Implementation of utils::recover())

Initial release