Merge lp://staging/~ev/daisy/weighted-tests into lp://staging/daisy

> + # On the first day we had any error reports, the weighting would be 0
> + # because 0 days have past since the first report.

"passed"

> + # The second report is one day after the first and the only report of
> + # the day.
> + self.assertEqual(weights[timestamps[1] / 1e6], 1/90.0)
> +
> + # The third report is two days after the first and the only report of
> + # the day.
> + self.assertEqual(weights[timestamps[2] / 1e6], 2/90.0)

Commas after "first" would make these comments easier to understand.

> + working_date = target_date - datetime.timedelta(days=89)
>...
> + adj = min(day_difference, 90) / 90.0

These lines are far apart from each other and not obviously related. So if later we decide to change the ramp-up to 30 days, for example (improving responsiveness at the expense of spikes), you or someone else might easily change the latter while forgetting the former. I suggest using the same constant in both lines (e.g. datetime.timedelta(days=RAMPUP-1)), and including a comment explaining what it's for.

+def main(release, start, end, verbose=False):
+ start = start.replace(hour=0, minute=0, second=0, microsecond=0)
+ end = end.replace(hour=0, minute=0, second=0, microsecond=0)
+
+ creds = {'username': config.cassandra_username,
+ 'password': config.cassandra_password}
+ pool = pycassa.ConnectionPool(config.cassandra_keyspace,
+ config.cassandra_hosts, timeout=600,
+ credentials=creds)
+
+ systems = pycassa.ColumnFamily(pool, 'SystemsForErrorsByRelease')
+ uniquesys = pycassa.ColumnFamily(pool, 'UniqueSystemsForErrorsByRelease')
+
+ while start <= end:
+ target_date = start.replace(hour=0, minute=0, second=0, microsecond=0)

hour, minute, second and microsecond are replace two times for start.

RAMP_UP is set to 90 in two separate python files. Perhaps this should be a config option somewhere instead?

+def weight(release='Ubuntu 12.04'):

Well, we talked about that.