code: func TempUnit(contents string) (string, error) {
  	tmp, err := ioutil.TempFile(os.TempDir(), "fleet-test-unit-")
  	if err != nil {
  		return "", err
  	}
  
  	tmp.Write([]byte(contents))
  	tmp.Close()
  
  	svc := fmt.Sprintf("%s.service", tmp.Name())
  	err = os.Rename(tmp.Name(), svc)
  	if err != nil {
  		os.Remove(tmp.Name())
  		return "", err
  	}
  
  	return svc, nil
  }
docs: // tempUnit creates a local unit file with the given contents, returning
  // the name of the file