[CentOS] yum in test mode and downgrade of a package

Bernard Fay wrote:
> Is it possible to run yum in test mode?    Something similar to rpm --test
> ...
yum -?
<snip>
usage: yum [options] COMMAND

List of Commands:

check-update   Check for available package updates
clean          Remove cached data
deplist        List a package's dependencies
downgrade      downgrade a package
<snip>

       mark