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())
    }