Use existing check functions

Author: hadley

NEWS.md

@@ -1,5 +1,6 @@
 # testthat (development version)
 
+* `local_edition()` now gives a useful error for bad values (#1547).
 * testthat now requires R 4.1.
 * `expect_s4_class()` now supports unquoting (@stibu81, #2064).
 * `it()` now finds the correct evaluation environment in more cases (@averissimo, #2085).

R/edition.R

@@ -51,14 +51,6 @@ edition_name <- function(x) {
   }
 }
 
-is_valid_edition <- function(x) {
-  if (is_zap(x)) {
-    TRUE
-  } else {
-    is.numeric(x) && length(x) == 1 && x %in% c(2, 3)
-  }
-}
-
 #' Temporarily change the active testthat edition
 #'
 #' `local_edition()` allows you to temporarily (within a single test or
@@ -69,10 +61,7 @@ is_valid_edition <- function(x) {
 #' @param x Edition Should be a single integer.
 #' @param .env Environment that controls scope of changes. For expert use only.
 local_edition <- function(x, .env = parent.frame()) {
-  if (!is_valid_edition(x)) {
-    stop("Available editions are 2 and 3", call. = FALSE)
-  }
-
+  check_number_whole(x, min = 2, max = 3)
   local_bindings(edition = x, .env = the, .frame = .env)
 }
 

tests/testthat/_snaps/edition.md

@@ -1,3 +1,16 @@
+# checks its inputs
+
+    Code
+      local_edition("x")
+    Condition
+      Error in `local_edition()`:
+      ! `x` must be a whole number, not the string "x".
+    Code
+      local_edition(5)
+    Condition
+      Error in `local_edition()`:
+      ! `x` must be a whole number between 2 and 3, not the number 5.
+
 # deprecation only fired for newer edition
 
     Code

tests/testthat/test-edition.R

@@ -6,15 +6,11 @@ test_that("can locally override edition", {
   expect_equal(edition_get(), 2)
 })
 
-test_that("only existing editions can be set", {
-  expect_error(
-    local_edition(5),
-    regexp = "Available editions are 2 and 3"
-  )
-  expect_error(
-    local_edition(-1),
-    regexp = "Available editions are 2 and 3"
-  )
+test_that("checks its inputs", {
+  expect_snapshot(error = TRUE, {
+    local_edition("x")
+    local_edition(5)
+  })
 })
 
 test_that("deprecation only fired for newer edition", {
@@ -45,7 +41,8 @@ test_that("edition for non-package dir is 2", {
 })
 
 test_that("can set the edition via an environment variable", {
-  local_edition(zap())
+  local_bindings(edition = zap(), .env = the)
+  
   withr::local_envvar(TESTTHAT_EDITION = 2)
   expect_equal(edition_get(), 2)