Add XML header with version and encoding when rendering an XML response

render/auto_test.go

@@ -45,7 +45,7 @@ func Test_Auto_XML(t *testing.T) {
 	w := willie.New(app)
 
 	res := w.XML("/cars").Get()
-	r.Equal("<string>Honda</string>\n<string>Toyota</string>\n<string>Ford</string>\n<string>Chevy</string>", strings.TrimSpace(res.Body.String()))
+	r.Equal("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<string>Honda</string>\n<string>Toyota</string>\n<string>Ford</string>\n<string>Chevy</string>", strings.TrimSpace(res.Body.String()))
 }
 
 func Test_Auto_HTML_List(t *testing.T) {

render/xml.go

@@ -14,6 +14,7 @@ func (s xmlRenderer) ContentType() string {
 }
 
 func (s xmlRenderer) Render(w io.Writer, data Data) error {
+	io.WriteString(w, xml.Header)
 	enc := xml.NewEncoder(w)
 	enc.Indent("", "  ")
 	return enc.Encode(s.value)

render/xml_test.go

@@ -29,6 +29,6 @@ func Test_XML(t *testing.T) {
 		bb := &bytes.Buffer{}
 		err := re.Render(bb, nil)
 		r.NoError(err)
-		r.Equal("<user>\n  <Name>mark</Name>\n</user>", strings.TrimSpace(bb.String()))
+		r.Equal("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<user>\n  <Name>mark</Name>\n</user>", strings.TrimSpace(bb.String()))
 	}
 }