Add a more verbose comment
Add more info to doc string
Factor out base test class and be explicit about what status code is expected
Prep tests for transactions and add new test case for creating a zone on top of another zone
Refactor create_zone function to use tranransactions and to allow creation of zones on top of an existing zone
Since an SOA is assinged to nameserver records before they are created in the new `create_zone`, we now see incremental build tasks being created
Create nameserver records *before* associating SOA record

Inventory will error out if you try to create a zone (asign a new SOA to
a domain) and do not have NS records in the zone. This patch changes the
create_zone behavior to create NS records for a zone's root domain
before assinging the new SOA record. This also means dns build jobs are
not scheduled when the NS records are added (because their domain
doesn't have a SOA yet) so the tests were also updated to reflect that
change.