Testing DNS records is easy once you know how. However, it is a task that that might never be completed by many in computing as once setup it rarely needs changing.
However, such testing is usually
only necessary where the domain being tranferred has
custom DNS records (if the domain to be transferred will
use hosting and email on the new target server there is no
need for these tests).
To test the DNS, which is
very useful prior to changing the nameservers:
For further assistance please see our: DNS FAQ.