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.
Actually this was already the case for certain commands, but some of them
was left unguarded for such cases. This commit also fixes#109.
The behaviour of silently skipping key prefixing when a command has no
arguments may change in the future so we added explicit tests as guards
for future changes. Predis\Command\Processor\KeyPrefixProcessor will
continue to skip key prefixing on empty arguments, regardless.