'L{URL.child} appends a new path segment, but does not affect the query
or fragment.'

def test_child(self):

    urlpath = URL.fromText(theurl)
    self.assertEqual(u'http://www.foo.com/a/nice/path/gong?zot=23&zut', urlpath.child(u'gong').asText())
    self.assertEqual(u'http://www.foo.com/a/nice/path/gong%2F?zot=23&zut', urlpath.child(u'gong/').asText())
    self.assertEqual(u'http://www.foo.com/a/nice/path/gong%2Fdouble?zot=23&zut', urlpath.child(u'gong/double').asText())
    self.assertEqual(u'http://www.foo.com/a/nice/path/gong%2Fdouble%2F?zot=23&zut', urlpath.child(u'gong/double/').asText())
