diff -u b/core/tests/Drupal/FunctionalJavascriptTests/Core/JsMessageTest.php b/core/tests/Drupal/FunctionalJavascriptTests/Core/JsMessageTest.php
--- b/core/tests/Drupal/FunctionalJavascriptTests/Core/JsMessageTest.php
+++ b/core/tests/Drupal/FunctionalJavascriptTests/Core/JsMessageTest.php
@@ -46,7 +46,7 @@
         $msg_element = $web_assert->waitForElementVisible('css', $selector);
         $this->assertNotEmpty($msg_element, "Message element visible: $selector");
         $web_assert->elementContains('css', $selector, "This is a message of the type, $type. You be the the judge of its importance.");
-        $current_messages[$selector] = ucfirst($type) . " message This is a message of the type, $type. You be the the judge of its importance.";
+        $current_messages[$selector] = "This is a message of the type, $type. You be the the judge of its importance.";
         $this->assertCurrentMessages($current_messages, $messagesSelector);
       }
       // Remove messages 1 by 1 and confirm the messages are expected.