diff --git a/core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.services.yml b/core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.services.yml
new file mode 100644
index 0000000..b23d938
--- /dev/null
+++ b/core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.services.yml
@@ -0,0 +1,5 @@
+services:
+  config_translation_test_event_subscriber:
+    class: Drupal\config_translation_test\EventSubscriber\ConfigTranslationTestSubscriber
+    tags:
+      - {name: event_subscriber}
diff --git a/core/modules/config_translation/tests/modules/config_translation_test/src/EventSubscriber/ConfigTranslationTestSubscriber.php b/core/modules/config_translation/tests/modules/config_translation_test/src/EventSubscriber/ConfigTranslationTestSubscriber.php
new file mode 100644
index 0000000..a2e794f
--- /dev/null
+++ b/core/modules/config_translation/tests/modules/config_translation_test/src/EventSubscriber/ConfigTranslationTestSubscriber.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace Drupal\config_translation_test\EventSubscriber;
+
+use Drupal\config_translation\Event\ConfigMapperEvent;
+use Drupal\config_translation\Event\ConfigTranslationEvents;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+
+class ConfigTranslationTestSubscriber implements EventSubscriberInterface {
+  static function getSubscribedEvents() {
+    $events[ConfigTranslationEvents::POPULATE_MAPPER][] = ['addConfigNames'];
+    return $events;
+  }
+
+  public function addConfigNames(ConfigMapperEvent $event) {
+    $mapper = $event->getMapper();
+    $mapper->addConfigName('config_translation_test.content');
+  }
+
+}
diff --git a/core/modules/config_translation/tests/src/Kernel/ConfigMapperTest.php b/core/modules/config_translation/tests/src/Kernel/ConfigMapperTest.php
new file mode 100644
index 0000000..59ff72e
--- /dev/null
+++ b/core/modules/config_translation/tests/src/Kernel/ConfigMapperTest.php
@@ -0,0 +1,47 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\config_translation\Kernel\ConfigMapperTest.
+ */
+
+namespace Drupal\Tests\config_translation\Kernel;
+
+use Drupal\Core\Routing\RouteMatch;
+use Drupal\KernelTests\KernelTestBase;
+use Symfony\Component\Routing\Route;
+
+/**
+ * 
+ *
+ * @group config_translation
+ */
+class ConfigMapperTest extends KernelTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['config_translation', 'config_translation_test'];
+
+  /**
+   * Tests adding config names to mapper.
+   */
+  public function testAddingConfigNames() {
+    // Get a config names mapper.
+    $manager = $this->container->get('plugin.manager.config_translation.mapper');
+    $mappers = $manager->getMappers();
+    //$mapper = $mappers['system.site_information_settings'];
+
+    // Test that it doesn't contain a config name from config_translation_test.
+    //$config_names = $mapper->getConfigNames();
+    //$this->assertFalse(in_array('config_translation_test.content', $config_names));
+
+    // Call populateFromRouteMatch() to dispatch an event.
+    //$mapper->populateFromRouteMatch(new RouteMatch('test', new Route('/')));
+
+    // Test that it now contains the new config name from config_translation_test.
+    //$config_names = $mapper->getConfigNames();
+    //$this->assertTrue(in_array('config_translation_test.content', $config_names));
+  }
+
+}