Align with withr::local_language() from dev withr

DESCRIPTION

@@ -35,7 +35,7 @@ Imports:
     rlang (>= 1.1.1),
     utils,
     waldo (>= 0.5.1),
-    withr (>= 2.5.0)
+    withr (>= 3.0.2)
 Suggests:
     covr,
     curl (>= 0.9.5),
@@ -55,4 +55,4 @@ Config/testthat/parallel: true
 Config/testthat/start-first: watcher, parallel*
 Encoding: UTF-8
 Roxygen: list(markdown = TRUE, r6 = FALSE)
-RoxygenNote: 7.2.3
+RoxygenNote: 7.3.2

NEWS.md

@@ -1,5 +1,9 @@
 # testthat (development version)
 
+* `LANGUAGE` is now set to `"C"` in reprocucible environments (i.e.
+  `test_that()` blocks) to disable translations. This fixes warnings
+  about being unable to set the language to `"en"` (#1925).
+
 # testthat 3.2.1
 
 * Fix incorrect format string detected by latest R-devel. Fix thanks to 

R/local.R

@@ -98,7 +98,7 @@ local_reproducible_output <- function(width = 80,
                                       unicode = FALSE,
                                       rstudio = FALSE,
                                       hyperlinks = FALSE,
-                                      lang = "en",
+                                      lang = "C",
                                       .env = parent.frame()) {
 
   if (unicode) {
@@ -133,10 +133,7 @@ local_reproducible_output <- function(width = 80,
     .local_envir = .env
   )
 
-  if (isTRUE(capabilities("NLS")) && Sys.getenv("LANG") != "C") {
-    withr::local_language(lang, .local_envir = .env)
-  }
-
+  withr::local_language(lang, .local_envir = .env)
   withr::local_collate("C", .local_envir = .env)
 }
 

tests/testthat/test-local.R

@@ -21,7 +21,7 @@ test_that("local context is 'as promised' inside test_that()", {
   expect_equal(getOption("max.print"), 99999)
 
   expect_equal(Sys.getenv("RSTUDIO"), "")
-  expect_equal(Sys.getenv("LANGUAGE"), "en")
+  expect_equal(Sys.getenv("LANGUAGE"), "C")
 
   expect_equal(Sys.getlocale("LC_COLLATE"), "C")
 })