diff --git a/core/modules/language/src/Tests/LanguageBrowserDetectionUnitTest.php b/core/modules/language/src/Tests/LanguageBrowserDetectionUnitTest.php
index 62ee8e3..5717da8 100644
--- a/core/modules/language/src/Tests/LanguageBrowserDetectionUnitTest.php
+++ b/core/modules/language/src/Tests/LanguageBrowserDetectionUnitTest.php
@@ -186,6 +186,12 @@ function testUIBrowserLanguageMappings() {
     $edit = array();
     $this->drupalPostForm('admin/config/regional/language/detection/browser/delete/' . $browser_langcode, $edit, t('Confirm'));
 
+    // We need raw here because %browser will add HTML.
+    $t_args = array(
+      '%browser' => $this->browserLangcode,
+    );
+    $this->assertRaw(t('The mapping for the %browser browser language code has been deleted.', $t_args), 'The test browser language code has been deleted.');
+
     // Check that ch-zn no longer exists.
     $this->assertNoField('edit-mappings-zh-cn-browser-langcode', 'Chinese browser language code no longer exists.');