diff --git a/core/modules/simpletest/src/AssertXpathTrait.php b/core/modules/simpletest/src/AssertXpathTrait.php
index 1535bee..5a00d97 100644
--- a/core/modules/simpletest/src/AssertXpathTrait.php
+++ b/core/modules/simpletest/src/AssertXpathTrait.php
@@ -64,7 +64,7 @@ protected function assertNoFieldByXPath($xpath, $value = NULL, $message = '', $g
       $found = FALSE;
       if ($fields) {
         foreach ($fields as $field) {
-          if ($field['value'] == $value) {
+          if ($field->getAttribute('value') === $value) {
             $found = TRUE;
           }
         }
diff --git a/core/tests/Drupal/FunctionalTests/BrowserTestBaseTest.php b/core/tests/Drupal/FunctionalTests/BrowserTestBaseTest.php
index 0024048..343be42 100644
--- a/core/tests/Drupal/FunctionalTests/BrowserTestBaseTest.php
+++ b/core/tests/Drupal/FunctionalTests/BrowserTestBaseTest.php
@@ -94,14 +94,14 @@ public function testAssertions() {
     $this->drupalLogin($account);
 
     $this->drupalGet('admin/people');
-    $this->assertFieldByXpath('//table/tbody/tr[2]/td[1]/span', $account->getAccountName());
+    $this->assertFieldByXPath('//table/tbody/tr[2]/td[1]/span', $account->getAccountName());
 
     $this->drupalGet('user/' . $account->id() . '/edit');
-    $this->assertFieldByXpath("//input[@id = 'edit-name']", $account->getAccountName());
-    $this->assertFieldByXpath("//select[@id = 'edit-timezone--2']", 'Australia/Sydney');
+    $this->assertFieldByXPath("//input[@id = 'edit-name']", $account->getAccountName());
+    $this->assertFieldByXPath("//select[@id = 'edit-timezone--2']", 'Australia/Sydney');
 
     $this->assertNoFieldByXPath('//notexisting');
-    $this->assertNoFieldByXpath("//input[@id = 'edit-name']", 'wrong value');
+    $this->assertNoFieldByXPath("//input[@id = 'edit-name']", 'wrong value');
   }
 
 }