diff --git a/core/.eslintignore b/core/.eslintignore
index ac3272e162..fae394892b 100644
--- a/core/.eslintignore
+++ b/core/.eslintignore
@@ -1,6 +1,6 @@
 assets/vendor/**/*
-modules/locale/tests/locale_test.js
 node_modules/**/*
 **/js_test_files/**/*
 *.js
 !*.es6.js
+modules/locale/tests/locale_test.es6.js
diff --git a/core/modules/locale/tests/src/Functional/LocaleJavascriptTranslationTest.php b/core/modules/locale/tests/src/Functional/LocaleJavascriptTranslationTest.php
index bbb825832b..55582ba0c0 100644
--- a/core/modules/locale/tests/src/Functional/LocaleJavascriptTranslationTest.php
+++ b/core/modules/locale/tests/src/Functional/LocaleJavascriptTranslationTest.php
@@ -21,8 +21,14 @@ class LocaleJavascriptTranslationTest extends BrowserTestBase {
   public static $modules = ['locale', 'locale_test'];
 
   public function testFileParsing() {
-    $filename = __DIR__ . '/../../locale_test.js';
 
+    // Testing the original file.
+    $files[] = __DIR__ . '/../../locale_test.es6.js';
+
+    // Testing the processed file.
+    $files[] = __DIR__ . '/../../locale_test.js';
+
+    foreach ($files as $filename) {
       // Parse the file to look for source strings.
       _locale_parse_js_file($filename);
 
@@ -89,6 +95,7 @@ public function testFileParsing() {
 
       $this->assertEqual(count($source_strings), count($test_strings), 'Found correct number of source strings.');
     }
+  }
 
   /**
    * Assert translations JS is added before drupal.js, because it depends on it.