Please don't use build tags for integration tests: https://peter.bourgon.org/blog/2021/04/02/dont-use-build-tag...
Along with the issues listed here you will run into issues with editors not building/linting your tests files because they have build tags that the editor is unaware of.
You can also put the environment variable in a TestMain[1] to cover an entire package of integration tests:
func TestMain(m *testing.M) {
if os.Getenv("RUN_INTEGRATION_TESTS") == "" {
fmt.Println("Skipping integration tests")
return
}
os.Exit(m.Run())
}