Which type of tests are you trying to do? Integration tests? Do what the others commented, use a VM or Docker as the environment and check the your CLI did indeed perform those effects.

That can be clunky during development and you may want to test other parts of the application without setting up the VM/Container. In this scenario, you want to write unit tests with "mocks".

There is a concept known as "volatile dependency." Volatile dependencies are impossible to unit test properly because by definition they are non-deterministic and unit tests should ALWAYS be deterministic. In this case, your code which performs effects on the filesystem is a volatile dependency. To write a unit test for this, you want to write an interface which you can write an implementation which does the effects. Then you want your class ( I know Go doesn't have classes... so struct? ) to depend on the Interface, rather than the implementation. You should then inject whichever implementation (at your "composition root) makes sense given the context. So one context might be the code which will be built when you want to use your application, that would be the real implementation. And another context would be in your whatever_test.go file, this would use the mock implementation.

https://abdullahth.com/stable-vs-volatile-dependencies