package test_json

import (
	"json"
	"os"
	"reflect"
	"testing"
)

func isNil(x interface{}) bool {
	if x == nil {
		return true
	}

	switch value := reflect.ValueOf(x); value.Kind() {
	case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map,
		reflect.Ptr, reflect.Slice:
		return value.IsNil()
	}

	return false
}

func TestJsonRoundtrip(t *testing.T) {
	type MyType struct {
		Buf []byte
		Ptr *int
		Map map[string]string
	}

	var testMyType MyType = MyType{nil, nil, nil}
	var myType MyType
	var bytes []byte
	var err os.Error

	if bytes, err = json.Marshal(&testMyType); err != nil {
		t.Fatal("Error ", err, " marshalling type ", testMyType)
	}

	t.Log("Marshaled type ", &testMyType, " to ", string(bytes))

	if err = json.Unmarshal(bytes, &myType); err != nil {
		t.Fatal("Error ", err, " unmarshalling bytes ", string(bytes))
	}

	if !isNil(myType.Buf) {
		t.Error("Buf not nil: ",myType.Buf)
	}
	if !isNil(myType.Ptr) {
		t.Error("Ptr not nil: ",myType.Ptr)
	}
	if !isNil(myType.Map) {
		t.Error("Map not nil: ", myType.Map)
	}
}