msgpack: add string() for datetime

Added a datetime type conversion function to a string, added tests for this function.

Added #322

Author: babyTsakhes

datetime/datetime.go

@@ -350,6 +350,11 @@ func datetimeDecoder(d *msgpack.Decoder, v reflect.Value, extLen int) error {
 	return ptr.UnmarshalMsgpack(b)
 }
 
+// This method converts Datetime to String - formats to ISO8601.
+func (d Datetime) String() string {
+	return d.time.Format(time.RFC3339Nano)
+}
+
 func init() {
 	msgpack.RegisterExtDecoder(datetimeExtID, Datetime{}, datetimeDecoder)
 	msgpack.RegisterExtEncoder(datetimeExtID, Datetime{}, datetimeEncoder)

datetime/datetime_test.go

@@ -1174,6 +1174,23 @@ func runTestMain(m *testing.M) int {
 	return m.Run()
 }
 
+func TestDatetimeString(t *testing.T) {
+
+	tm, _ := time.Parse(time.RFC3339Nano, "2010-05-24T17:51:56.000000009Z")
+	dt, err := MakeDatetime(tm)
+	if err != nil {
+		t.Fatalf("Unable to create Datetime from %s: %s", tm, err)
+	}
+
+	result := dt.String()
+	t.Logf("Result: %s", result)
+
+	expected := "2010-05-24T17:51:56.000000009Z"
+	if result != expected {
+		t.Errorf("Expected %s, got %s", expected, result)
+	}
+
+}
 func TestMain(m *testing.M) {
 	code := runTestMain(m)
 	os.Exit(code)