Tests getting and assigning values to document.body

On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".

PASS successfullyParsed is true

TEST COMPLETE

PASS frame.contentDocument.body = document.createElement("div") threw exception HierarchyRequestError: Failed to set the 'body' property on 'Document': The new body element is of type 'DIV'. It must be either a 'BODY' or 'FRAMESET' element..
PASS frame.contentDocument.body = document.createElement("frameset") did not throw exception.
PASS frame.contentDocument.documentElement.childNodes.length is 2
PASS frame.contentDocument.body = document.createElement("body") did not throw exception.
PASS frame.contentDocument.documentElement.childNodes.length is 2
PASS observer.takeRecords().length is 0
PASS frame.contentDocument.body is newBody
PASS frame.contentDocument.body is newBody
PASS frame.contentDocument.body.tagName is "BODY"