atom: Stop unescaping special HTML characters

The HTML data in Atom is escaped because the data needs to put as a
string to an XML file. If we are accessing it by reading the string
value, then it is already unescaped, as opposed to getting the raw
XML data.

XHTML data don't need to be unescaped either since the elements are
already encoded as is in tree. :)

Closes #198

src/parser/atom.go

@@ -3,7 +3,6 @@ package parser
 
 import (
 	"encoding/xml"
-	"html"
 	"io"
 	"strings"
 
@@ -58,7 +57,7 @@ func (a *atomText) String() string {
 	if a.Type == "xhtml" {
 		data = a.XML
 	}
-	return html.UnescapeString(strings.TrimSpace(data))
+	return strings.TrimSpace(data)
 }
 
 func (links atomLinks) First(rel string) string {

src/parser/atom_test.go

@@ -214,3 +214,19 @@ func TestAtomLinkInID(t *testing.T) {
 		t.Fatalf("\nwant: %#v\nhave: %#v\n", want, have)
 	}
 }
+
+func TestAtomDoesntEscapeHTMLTags(t *testing.T) {
+	feed, _ := Parse(strings.NewReader(`
+		<?xml version="1.0" encoding="utf-8"?>
+		<feed xmlns="http://www.w3.org/2005/Atom">
+			<entry><summary type="html">&amp;lt;script&amp;gt;alert(1);&amp;lt;/script&amp;gt;</summary></entry>
+		</feed>
+	`))
+	have := feed.Items[0].Content
+	want := "&lt;script&gt;alert(1);&lt;/script&gt;"
+	if !reflect.DeepEqual(want, have) {
+		t.Logf("want: %#v", want)
+		t.Logf("have: %#v", have)
+		t.FailNow()
+	}
+}