test: add i18n smoke test

Makes sure that all of the languages that Anubis supports show up when
the challenge page is sent to a client.

Signed-off-by: Xe Iaso <me@xeiaso.net>

test/i18n/test.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+function cleanup() {
+  pkill -P $$
+}
+
+trap cleanup EXIT SIGINT
+
+# Build static assets
+(cd ../.. && npm ci && npm run assets)
+
+# Spawn three jobs:
+
+# HTTP daemon that listens over a unix socket (implicitly ./unixhttpd.sock)
+go run ../cmd/unixhttpd &
+
+go tool anubis \
+  --policy-fname ./anubis.yaml \
+  --use-remote-address \
+  --target=unix://$(pwd)/unixhttpd.sock &
+
+go run ../cmd/backoff-retry node ./test.mjs