- DateTime on JRuby 1.7.5 only allows offsets of less than 1 day. Change
uses of 1 day offsets to 1 hour.
- JRuby 1.7.5 considers DateTime instances that differ by less than 1
millisecond to be equivalent
(jruby/jruby#1311). Make tests that rely on
being able to distinguish differences of 1 microsecond adapt if the
platform doesn't support such comparisons.