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).
Below are two videos which show:
Video 1 - first part.
Video 2, second part:
This page is a further explanation to the basic DNS testing method shown in our DNS FAQ.