local_test_context: Locally set options for maximal test reproducibility

In r-lib/testthat: Unit Testing for R

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,
  rstudio = FALSE,
  hyperlinks = FALSE,
  lang = "en",
  .env = parent.frame()
)

Arguments

.env	Environment to use for scoping; expert use only.
width	Value of the "width" option.
crayon	Determines whether or not crayon (now cli) colour should be applied.
unicode	Value of the "cli.unicode" option. The test is skipped if l10n_info()$`UTF-8` is FALSE.
rstudio	Should we pretend that we're inside of RStudio?
hyperlinks	Should we use ANSI hyperlinks.
lang	Optionally, supply a BCP47 language code to set the language used for translating error messages. This is a lower case two letter ISO 639 country code, optionally followed by "_" or "-" and an upper case two letter ISO 3166 region code.

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.

• cli.condition_width = Inf so that new lines introduced while width-wrapping condition messages don't interfere with message matching.

• crayon.enabled (default: FALSE) suppresses ANSI colours generated by the cli and crayon packages (normally colours are used if cli detects that you're in a terminal that supports colour).

• cli.num_colors (default: 1L) Same as the crayon option.

• lifecycle_verbosity = "warning" so that every lifecycle problem always generates a warning (otherwise deprecated functions don't generate a warning every time).

• max.print = 99999 so the same number of values are printed.

• 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(cli::col_blue("Text will not be colored"))
  cat(cli::symbol$ellipsis)
  cat("\n")
})
test_that("test ellipsis", {
  local_reproducible_output(unicode = FALSE)
  expect_equal(cli::symbol$ellipsis, "...")

  local_reproducible_output(unicode = TRUE)
  expect_equal(cli::symbol$ellipsis, "\u2026")
})

r-lib/testthat documentation built on Feb. 18, 2024, 8:59 p.m.