This is a testharness.js-based test.
Harness Error. harness_status.status = 1 , harness_status.message = 2 duplicate test names: "createElement(): 6.1.5. If result has children, then throw a NotSupportedError", "createElementNS(): 6.1.5. If result has children, then throw a NotSupportedError"
PASS createElement(): Pre-flight check should succeed 
PASS createElement(): 5. Create a customized built-in element 
PASS createElement(): 6. Create an autonomous custom element 
PASS createElement(): 6.1.2. Errors in Construct(C) should be reported 
PASS createElement(): 6.1.3. If result does not implement the HTMLElement interface, throw a TypeError 
PASS createElement(): 6.1.4. If result's attribute list is not empty, then throw a NotSupportedError 
PASS createElement(): 6.1.5. If result has children, then throw a NotSupportedError 
PASS createElement(): 6.1.5. If result has children, then throw a NotSupportedError 
PASS createElement(): 6.1.6. If result's parent is not null, then throw a NotSupportedError 
PASS createElement(): 6.1.7. If result's node document is not document, then throw a NotSupportedError 
PASS createElement(): 6.1.8. If result's namespace is not the HTML namespace, then throw (a NotSupportedError, currently TypeError) 
PASS createElement(): 6.1.9. If result's local name is not equal to localName, then throw a NotSupportedError 
PASS createElementNS(): Pre-flight check should succeed 
PASS createElementNS(): 5. Create a customized built-in element 
PASS createElementNS(): 6. Create an autonomous custom element 
PASS createElementNS(): 6.1.2. Errors in Construct(C) should be reported 
PASS createElementNS(): 6.1.3. If result does not implement the HTMLElement interface, throw a TypeError 
PASS createElementNS(): 6.1.4. If result's attribute list is not empty, then throw a NotSupportedError 
PASS createElementNS(): 6.1.5. If result has children, then throw a NotSupportedError 
PASS createElementNS(): 6.1.5. If result has children, then throw a NotSupportedError 
PASS createElementNS(): 6.1.6. If result's parent is not null, then throw a NotSupportedError 
PASS createElementNS(): 6.1.7. If result's node document is not document, then throw a NotSupportedError 
PASS createElementNS(): 6.1.8. If result's namespace is not the HTML namespace, then throw (a NotSupportedError, currently TypeError) 
PASS createElementNS(): 6.1.9. If result's local name is not equal to localName, then throw a NotSupportedError 
Harness: the test ran to completion.