Usually integration tests take long time, because they’re doing real requests to real system. And it’s not necessary to run them every time we type go test. For example we have Golang client to work with PayPal SDK, it has some exported functions to send data to PayPal, then parse response and handle errors. So I wrote test functions to check that our client works properly with the real system, and be aware if PayPal changes response format or error codes. Also I have some client tests to check client types and validations, pure unit tests. And I want to launch only these tests when I do go test or when tests are triggered by CI system.

The first thing I did is that I splitted tests into 2 files (unit_test.go and integration_test.go), but you can have more files. The main idea is mark your _test.go files with build constraints:

// +build integration

package paypalsdk

And run Integration tests with tags flag:

go test -tags=integration

When you do not pass tags only Unit tests will be executed:

go test