diff --git a/tests/src/Functional/EmailRegistrationTestCase.php b/tests/src/Functional/EmailRegistrationTestCase.php
index 161fa96..e9f0800 100644
--- a/tests/src/Functional/EmailRegistrationTestCase.php
+++ b/tests/src/Functional/EmailRegistrationTestCase.php
@@ -68,8 +68,9 @@ class EmailRegistrationTestCase extends BrowserTestBase {
       'pass' => $pass,
     ];
     $this->drupalPostForm('user/login', $login, 'Log in');
-    $error_message = $this->xpath('//div[contains(@class, "error")]');
-    $this->assertNotEmpty($error_message, 'When login_with_username is false, a user cannot login with just their username.');
+    // When login_with_username is false, a user cannot login with just their
+    // username.
+    $this->assertSession()->responseContains('Unrecognized email address or password.');
 
     // Set login_with_username to TRUE and try to login with just username.
     $email_registration_config->set('login_with_username', TRUE)->save();