def testUsefulness(self):
'Test that accessing usefulness gives correct result. Fails every DST change.'
sdfile = ScanDigestFile(self.owner, url=self.url, location=self.location)
now = datetime.now()
utcnow = datetime.utcnow()
seconds_diff = utcnow - now
sdfile.hits = abs(seconds_diff.total_seconds() * 10)
sdfile.date = utcnow
actual = sdfile.usefulness
expected = 10.0
self.assertAlmostEqual(expected, actual, places=5)
