Separate test for time spent.
Separate test for time spent.

The pypy build was occasionally failing because the test was taking over
a second to run :/  All that I really care about here is that we are
rounding up so we never have a duration less than a millisecond.

https://travis-ci.org/sprockets/sprockets.mixins.sentry/jobs/70785679

sprockets/sprockets.mixins.sentry