What is the proper process for an Apex Unit Test

How many level of child records can be returned in a single SOQL query from one parent object

While writing an Apex class that creates Accounts, a developer wants to make sure that all required fields are handled properly.
Which approach should the developer use to be sure that the Apex class works correctly?

A developer needs to create a baseline set of data (Accounts, Contacts, Products, Assets) for an entire suite of tests allowing them to test independent requirements various types of Salesforce Cases. Which approach can efficiently generate the required data for each unit test?

A Licensed_Professional__c custom object exist in the system with two Master-Detail fields for the following objects: Certification__c and Contact. Users with the "Certification Representative" role can access the Certification records they own and view the related Licensed Professionals records, however users with the
"Salesforce representative" role report they cannot view any Licensed professional records even though they own the associated Contact record. What are two likely causes of users in the "Sales Representative" role not being able to access the Licensed Professional records? Choose 2 answers