httpmock VS go-sqlmock

We will use httpmock for this purpose. Inside function setupSuite(), where we created useCase and provided nil as a billingClient now we will pass mocked http client:

Alternatively, you could use an http mock library like https://github.com/jarcoal/httpmock, and override the urls the RealClient calls with a mock response in your tests.

To mock an API: https://github.com/jarcoal/httpmock to use when your code calls external APIs so you don't want your tests call the real API. No need to create an interface as you do.

For that, I used the lib go-sqlmock. So, for example, the following snippet is part of the person/service_test.go file:

It's not the right call IMO to skip mocking the database connection to achieve 100% test coverage. How your app will behave in failure scenarios that are impossible to imitate during integration tests is part of the software contract. If your choice is to panic, or return an error, document that by testing that behavior. If another dev, or future you inadvertently breaks the contract, the test suite will fail. That's what you want. For unit tests against your database you should be using either go-sqlmock if testing against database/sql or pgxmock if testing against pgx. That being said, the points raised elsewhere in this thread regarding unit tests potentially hiding edge cases in terms of how an actual database will interact with your application that are not reflective of your understanding when writing mocks are 100% valid. You should do both. Unit test your app and write integration tests as well. On my team, we run integration tests using docker-compose.

I use Sqlmock for that purpose

There is a good lib for db tests https://github.com/DATA-DOG/go-sqlmock