test: ensure Wrangler tests run in a deterministic locale

Author: petebacondarwin

packages/wrangler/package.json

@@ -61,7 +61,7 @@
 		"generate-json-schema": "pnpm exec ts-json-schema-generator --no-type-check --path src/config/config.ts --type RawConfig --out config-schema.json",
 		"prepublishOnly": "SOURCEMAPS=false pnpm run -w build",
 		"start": "pnpm run bundle && cross-env NODE_OPTIONS=--enable-source-maps ./bin/wrangler.js",
-		"test": "pnpm run assert-git-version && vitest",
+		"test": "pnpm run assert-git-version && LC_ALL=C vitest",
 		"test:ci": "pnpm run test run",
 		"test:debug": "pnpm run test --silent=false --verbose=true",
 		"test:e2e": "vitest -c ./e2e/vitest.config.mts",

packages/wrangler/src/__tests__/vitest.setup.ts

@@ -1,4 +1,5 @@
 /* eslint-disable @typescript-eslint/consistent-type-imports */
+import assert from "node:assert";
 import { resolve } from "path";
 import { PassThrough } from "stream";
 import chalk from "chalk";
@@ -22,8 +23,10 @@ chalk.level = 0;
 	global as unknown as { __RELATIVE_PACKAGE_PATH__: string }
 ).__RELATIVE_PACKAGE_PATH__ = "..";
 
-// Set `LC_ALL` to fix the language as English for the messages thrown by Yargs.
-process.env.LC_ALL = "en";
+assert(
+	process.env.LC_ALL === "C",
+	"Expected `LC_ALL` env var to be 'C' in order get deterministic localized messages in tests"
+);
 
 vi.mock("ansi-escapes", () => {
 	return {