'readfile() should skip over \'extra\' data present in the zip metadata.'

def test_extraData(self):

    fn = self.mktemp()
    with zipfile.ZipFile(fn, 'w') as zf:
        zi = zipfile.ZipInfo('0')
        zi.extra = 'hello,    extra'
        zf.writestr(zi, 'the    real    data')
    with zipstream.ChunkingZipFile(fn) as czf:
        with czf.readfile('0') as zfe:
            self.assertEqual(zfe.read(), 'the    real    data')
