[CustomElementRegistry.html]
  type: testharness
  [customElements.define must throw a NotSupportedError when there is already a custom element with the same class]
    expected: FAIL

  [customElements.define must get callbacks of the constructor prototype]
    expected: FAIL

  [customElements.define must get "observedAttributes" property on the constructor prototype when "attributeChangedCallback" is present]
    expected: FAIL

  [customElements.define must rethrow an exception thrown while getting observedAttributes on the constructor prototype]
    expected: FAIL

  [customElements.define must rethrow an exception thrown while converting the value of observedAttributes to sequence<DOMString>]
    expected: FAIL

  [customElements.define must rethrow an exception thrown while iterating over observedAttributes to sequence<DOMString>]
    expected: FAIL

  [customElements.define must rethrow an exception thrown while retrieving Symbol.iterator on observedAttributes]
    expected: FAIL

  [customElements.define must define an instantiatable custom element]
    expected: FAIL

  [customElements.define must upgrade elements in the shadow-including tree order]
    expected: FAIL

