This is a testharness.js-based test.
PASS offsetParent should return node in the same node tree in open shadow root.
PASS offsetParent should return node in the same node tree in closed shadow root.
PASS offsetParent should return an unclosed node in a open shadow from closed shadow.
PASS offsetParent should return an unclosed node in a closed shadow from open shadow.
PASS offsetParent should return an unclosed node.
FAIL offsetParent should skip any non-unclosed nodes. assert_array_equals: lengths differ, expected 1 got 0
PASS offsetParent should return node in the open shadow root because it is unclosed.
PASS offsetParent should return null in case position:fixed offsetParent is not unclosed.
PASS All position:static elements should be skipped for offsetParent.
Harness: the test ran to completion.

