diff -u b/core/modules/system/tests/src/Functional/Form/CheckboxTest.php b/core/modules/system/tests/src/Functional/Form/CheckboxTest.php
--- b/core/modules/system/tests/src/Functional/Form/CheckboxTest.php
+++ b/core/modules/system/tests/src/Functional/Form/CheckboxTest.php
@@ -100,17 +100,10 @@
       $name = (string) $checkbox->getAttribute('name');
       $this->assertSame($checked, $name == 'checkbox_off[0]' || $name == 'checkbox_zero_default[0]' || $name == 'checkbox_string_zero_default[0]', new FormattableMarkup('Checkbox %name correctly checked', ['%name' => $name]));
     }
-  }
 
-  /**
-   * Tests that checkbox has no aria required attribute.
-   */
-  public function testFormCheckboxHasNoAriaRequiredAtt() {
+    // Ensure that checkbox has no aria required attribute.
     $this->drupalGet('/form-test/checkbox');
-    $checkbox = $this->cssSelect('input[type=checkbox]');
-    $this->assertNotEmpty($checkbox);
-    $element = $checkbox[0]->getAttribute('aria-required');
-    $this->assertEmpty($element);
+    $this->assertEmpty($this->assertSession()->elementExists('css', 'input[type=checkbox][required]')->getAttribute('aria-required'));
   }
 
 }