Fix Header.Status

The size indices were not adjusted when we changed to int16 recently, which made it
overwrite the header status. Which shows the importance of good tests.

client_test.go

@@ -144,7 +144,7 @@ func TestExecTyped(t *testing.T) {
 		c.Assert(err, qt.IsNil)
 		c.Assert(len(logMessages), qt.Equals, 2)
 		c.Assert(string(logMessages[0].Body), qt.Equals, "first log message")
-		c.Assert(logMessages[0].Header.Status, qt.Equals, uint16(0))
+		c.Assert(logMessages[0].Header.Status, qt.Equals, uint16(150))
 		c.Assert(logMessages[0].Header.Version, qt.Equals, uint16(32))
 		c.Assert(client.Close(), qt.IsNil)
 	})

message.go

@@ -50,7 +50,7 @@ func (h *Header) Read(r io.Reader) error {
 	h.ID = binary.BigEndian.Uint32(buf[0:4])
 	h.Version = binary.BigEndian.Uint16(buf[4:6])
 	h.Status = binary.BigEndian.Uint16(buf[6:8])
-	h.Size = binary.BigEndian.Uint32(buf[6:])
+	h.Size = binary.BigEndian.Uint32(buf[8:])
 	return nil
 }
 
@@ -60,7 +60,7 @@ func (h Header) Write(w io.Writer) error {
 	binary.BigEndian.PutUint32(buff[0:4], h.ID)
 	binary.BigEndian.PutUint16(buff[4:6], h.Version)
 	binary.BigEndian.PutUint16(buff[6:8], h.Status)
-	binary.BigEndian.PutUint32(buff[6:], h.Size)
+	binary.BigEndian.PutUint32(buff[8:], h.Size)
 	_, err := w.Write(buff)
 	return err
 }

message_test.go

@@ -0,0 +1,34 @@
+package execrpc
+
+import (
+	"bytes"
+	"testing"
+
+	qt "github.com/frankban/quicktest"
+)
+
+func TestMessage(t *testing.T) {
+	c := qt.New(t)
+
+	m1 := Message{
+		Body: []byte("hello"),
+		Header: Header{
+			ID:      2,
+			Version: 3,
+			Status:  4,
+			Size:    5,
+		},
+	}
+
+	var b bytes.Buffer
+
+	c.Assert(m1.Header.Write(&b), qt.IsNil)
+	c.Assert(m1.Write(&b), qt.IsNil)
+
+	var m2 Message
+	c.Assert(m2.Header.Read(&b), qt.IsNil)
+	c.Assert(m2.Read(&b), qt.IsNil)
+
+	c.Assert(m2, qt.DeepEquals, m1)
+
+}