Improve XML decoder to remove illegal characters

reader/xml/decoder_test.go

@@ -0,0 +1,29 @@
+// Copyright 2019 Frédéric Guillot. All rights reserved.
+// Use of this source code is governed by the Apache 2.0
+// license that can be found in the LICENSE file.
+
+package xml // import "miniflux.app/reader/xml"
+
+import (
+	"encoding/xml"
+	"fmt"
+	"strings"
+	"testing"
+)
+
+func TestIllegalCharacters(t *testing.T) {
+	type myxml struct {
+		XMLName xml.Name `xml:"rss"`
+		Version string   `xml:"version,attr"`
+		Title   string   `xml:"title"`
+	}
+
+	data := fmt.Sprintf(`<?xml version="1.0" encoding="windows-1251"?><rss version="2.0"><title>%s</title></rss>`, "\x10")
+	var x myxml
+
+	decoder := NewDecoder(strings.NewReader(data))
+	err := decoder.Decode(&x)
+	if err != nil {
+		t.Error(err)
+	}
+}