func setupTestCase() {
	if err := os.MkdirAll(tempDir, 0700); err != nil {
		log.Println(err)
	}
}
setUp and tearDown
package httpapi
import (
	"log"
	"math/rand"
	"os"
	"testing"
)
const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"