config for test is separated and testMain is ready

config.go

 var Config AppConfig
 
 func readConfig() error {
-	log.Printf("Read configration from config.json")
-	body, err := ioutil.ReadFile("config.json")
+	return readConfigFile("config.json")
+}
+
+func readConfigFile(file string) error {
+
+	log.Printf("Read configration from %s", file)
+	body, err := ioutil.ReadFile(file)
 	if err != nil {
 		log.Fatal("Fatal error Cannot read config ..")
 		return err
 	fmt.Println(string(j))
 	return err
 }
+
+func readConfigForTest() error {
+	return readConfigFile("config.test.json")
+}

config.test.json

+{
+    "Rpn": {
+         "Url" : "https://deposit.paylomo.net/pay.php?r=payEasy",
+         "UrlTest" : "https://deposit-mac.chinapaytech.com/pay.php?r=payEasy",
+         "MD5P2P"   : "370296119874502",
+         "MD5FAT"   : "207841502473198"
+    },
+    "LeanWork" :{
+         "MD5Key"   :  "492815086935204" 
+    }
+}

main_test.go

+package main
+
+import (
+	"os"
+	"testing"
+)
+
+func TestMain(m *testing.M) {
+	// call flag.Parse() here if TestMain uses flags
+	readConfigForTest()
+	os.Exit(m.Run())
+}