| PASS | setter on DOMStringMap must enqueue an attributeChanged reaction when adding an observed data attribute | |
| PASS | setter on DOMStringMap must not enqueue an attributeChanged reaction when adding an unobserved data attribute | |
| PASS | setter on DOMStringMap must enqueue an attributeChanged reaction when mutating the value of an observed data attribute | |
| PASS | setter on DOMStringMap must enqueue an attributeChanged reaction when mutating the value of an observed data attribute to the same value | |
| PASS | setter on DOMStringMap must not enqueue an attributeChanged reaction when mutating the value of an unobserved data attribute | |
| PASS | deleter on DOMStringMap must enqueue an attributeChanged reaction when removing an observed data attribute | |
| PASS | deleter on DOMStringMap must not enqueue an attributeChanged reaction when removing an unobserved data attribute | |
| PASS | deleter on DOMStringMap must not enqueue an attributeChanged reaction when it does not remove a data attribute | |