add test and fix a decode bug

mqtt.go

@@ -160,8 +160,6 @@ func Decode(b []byte)*Mqtt{
             }
             mqtt.topics = topics
         }
-        default:
-            mqtt = nil
     }
     return mqtt
 }

mqtt_test.go

@@ -0,0 +1,64 @@
+package mqtt
+
+import (
+    "testing"
+    "fmt"
+    )
+
+func Test(t *testing.T){
+    mqtt := initTest()
+    fmt.Println("------ Origin MQTT Object")
+    printMqtt(mqtt)
+    fmt.Println("------ Encode To Binary")
+    bits := Encode(mqtt)
+    printBytes(bits)
+    fmt.Println("------ Decode To Object")
+    printMqtt(Decode(bits))
+}
+
+func initTest()*Mqtt{
+    mqtt := new(Mqtt)
+    mqtt.header = new(Header)
+    mqtt.header.messageType = MessageType(1)
+    mqtt.protocolName = "MQIsdp"
+    mqtt.protocolVersion = uint8(3)
+    mqtt.connectFlags = new(ConnectFlags)
+    mqtt.connectFlags.usernameFlag = true
+    mqtt.connectFlags.passwordFlag = true
+    mqtt.connectFlags.willRetain = false
+    mqtt.connectFlags.willQos = uint8(1)
+    mqtt.connectFlags.willFlag = true
+    mqtt.connectFlags.cleanSession = true
+    mqtt.keepAliveTimer = uint16(10)
+    mqtt.clientId = "xixihaha"
+    mqtt.willTopic = "topic"
+    mqtt.willMessage = "message"
+    mqtt.username = "name"
+    mqtt.password = "pwd"
+    return mqtt
+}
+
+func printByte(b byte){
+    out := make([]uint8, 8)
+    val := uint8(b)
+    for i := 1; val > 0;i += 1{
+        foo := val % 2
+        val = (val - foo) / 2
+        out[8 - i] = foo
+    }
+    fmt.Println(out)
+}
+
+func printBytes(b []byte){
+    for i := 0;i < len(b);i += 1{
+        printByte(b[i])
+    }
+}
+
+func printMqtt(mqtt *Mqtt){
+    fmt.Printf("MQTT = %+v\n", *mqtt)
+    fmt.Printf("Header = %+v\n", *mqtt.header)
+    if mqtt.connectFlags != nil{
+        fmt.Printf("ConnectFlags = %+v\n", *mqtt.connectFlags)
+    }
+}