comments added for test case

accessToken_test.go

 	"testing"
 )
 
+//get accesstoken from wechat server or local cache file
 func TestAccessToken(t *testing.T) {
 	readConfig()
 	token, err := GetAccessToken()
 	AssertEqual(t, token, WechatAccessToken.AccessToken, "Global accesstoken is not uptodate")
 }
 
+//save token to a file and read it back
 func TestTokenStorage(t *testing.T) {
 	var s AuthToken
 	s.AccessToken = "s0wf65p-KMzvYtH8qPu2qSX_EXLE2NaBgFHl7MZwedc7Kv_hdO0FG1QeUmBYJAGmQqJinPwFr67MRZwJee4rDnGVwhbuIfKs29N4ZJSXFP8fbAheuas08UuRe13UsdCtWSMcAFAGCW"
 	AssertEqual(t, s, token, "read token should be correct")
 }
 
+//read config, make sure its not empty
 func TestReadConfig(t *testing.T) {
-	readConfig()
+	SetupConfig()
 	if APIConfig.AppSecret == "" {
 		t.Error("AppSecret not available")
 	}