Github user mfenes commented on the issue:
https://github.com/apache/zookeeper/pull/375
The reason why I've created a test category for "slow" and not for "fast"
is because this way one can specify a test category by ant test
-Dtest.category=... and can exclude the "slow" tests from any category by using
the -Dtest.quick=yes option.
The special logic for "slow" is also needed for backwards compatibility
with the current ant test options.---
