We now have a base test case class for Predis (namely PredisTestCase)
grouping various commonly used utility methods shared by all of the
tests in the suite, greatly improving reusability.
NOTE: Backported from v0.9-dev.
Starting with 2.6, Redis uses a slightly different format for the payload
returned by MONITOR for each command. Predis can now adapt to this difference
and returns a new `client` field in the payload object. This new field is
always defined but is set to NULL when connected to Redis < 2.6.
Please note that Redis 2.6 now does not echo the `MONITOR` command as the
first payload when opening a new MONITOR context.