go.mod best practice

[michrag]

Hi everyone, just started this great course, I already have a doubt.

In https://quii.gitbook.io/learn-go-with-tests/go-fundamentals/hello-world it says
"In future chapters, you will need to run go mod init SOMENAME in each new folder before running commands like go test or go build.",
but then in https://quii.gitbook.io/learn-go-with-tests/go-fundamentals/integers it says instead:

Your project directory might look something like this:

learnGoWithTests
|
|-> helloworld
| |- hello.go
| |- hello_test.go
|
|-> integers
| |- adder_test.go
|
|- go.mod
|- README.md

(just one go.mod file in the root folder).

What is the best practice?
Thank you!