diff --git a/test/index.html b/test/index.html
index 4d63fee3b..fd4cfec13 100644
--- a/test/index.html
+++ b/test/index.html
@@ -109,7 +109,6 @@
 
     <script type="text/javascript" src="libphonenumber_util_test.js"></script>
     <script type="text/javascript" src="reliable_trigger_test.js"></script>
-    <script type="text/javascript" src="i18n_test.js"></script>
     <script type="text/javascript" src="stickers_test.js"></script>
 
     <script type="text/javascript">
diff --git a/test/i18n_test.js b/ts/test-both/types/setupI18n_test.ts
similarity index 68%
rename from test/i18n_test.js
rename to ts/test-both/types/setupI18n_test.ts
index 5371769ea..82674c0dc 100644
--- a/test/i18n_test.js
+++ b/ts/test-both/types/setupI18n_test.ts
@@ -1,15 +1,24 @@
-// Copyright 2017-2020 Signal Messenger, LLC
+// Copyright 2017-2022 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
 
-/* global i18n */
+import { assert } from 'chai';
+import type { LocalizerType } from '../../types/Util';
+import { setupI18n } from '../../util/setupI18n';
+import * as enMessages from '../../../_locales/en/messages.json';
+
+describe('setupI18n', () => {
+  let i18n: LocalizerType;
+
+  beforeEach(() => {
+    i18n = setupI18n('en', enMessages);
+  });
 
-describe('i18n', () => {
   describe('i18n', () => {
     it('returns empty string for unknown string', () => {
       assert.strictEqual(i18n('random'), '');
     });
     it('returns message for given string', () => {
-      assert.equal(i18n('reportIssue'), ['Contact Support']);
+      assert.strictEqual(i18n('reportIssue'), 'Contact Support');
     });
     it('returns message with single substitution', () => {
       const actual = i18n('migratingToSQLCipher', ['45/200']);