I loved this interview! Great questions and great discussion.

Here is a developed answer: softwareengineering.stackexchange.com/questions/42...

Yes. Go is built around single method interfaces. Data layer is often a repository interface set with multiple methods. You can mock each of those, but it is less effort for more benefit to use a real ephemeral data layer for testing, so mocking is typically skipped.

Yes you are right. Go community rarely mocks. In this case use a helper package that spins up a docker PG container just for testing, integration testing. There are several to choose from. I used the one call test containers or something.

Are you getting the notifications worked as well? GH website shows that I have unread notifications but the list is empty. I can however see the now banned repos listed as having unread items 🤷🏻‍♂️