return StatusOK from an empty ResponseHeader.StatusCode()

header.go

@@ -116,6 +116,9 @@ func (h *RequestHeader) SetByteRange(startPos, endPos int) {
 
 // StatusCode returns response status code.
 func (h *ResponseHeader) StatusCode() int {
+	if h.statusCode == 0 {
+		return StatusOK
+	}
 	return h.statusCode
 }
 
@@ -1386,9 +1389,6 @@ func (h *ResponseHeader) AppendBytes(dst []byte) []byte {
 	if statusCode < 0 {
 		statusCode = StatusOK
 	}
-	if statusCode == 0 {
-		statusCode = StatusOK
-	}
 	dst = append(dst, statusLine(statusCode)...)
 
 	server := h.Server()

header_test.go

@@ -10,6 +10,14 @@ import (
 	"testing"
 )
 
+func TestResponseHeaderDefaultStatusCode(t *testing.T) {
+	var h ResponseHeader
+	statusCode := h.StatusCode()
+	if statusCode != StatusOK {
+		t.Fatalf("unexpected status code: %d. Expecting %d", statusCode, StatusOK)
+	}
+}
+
 func TestResponseHeaderDelClientCookie(t *testing.T) {
 	cookieName := "foobar"