ts = filter(lambda t: t['id'] == i, r)
assert len(ts) == 1, "check scratched track appears exactly once in recent"
assert ts[0]['state'] == 'scratched', "checking track scratched"
ts = filter(lambda t: t['id'] == i, r)
assert len(ts) == 1, "check scratched track appears exactly once in recent"
assert ts[0]['state'] == 'scratched', "checking track scratched"