handle isPermalink in rss feeds

src/parser/rss_test.go

@@ -203,3 +203,28 @@ func TestRSSTitleHTMLTags(t *testing.T) {
 		}
 	}
 }
+
+func TestRSSIsPermalink(t *testing.T) {
+	feed, _ := Parse(strings.NewReader(`
+		<?xml version="1.0" encoding="UTF-8"?>
+		<rss version="2.0" xmlns:content="http://purl.org/rss/1.0/modules/content/">
+			<channel>
+				<item>
+                    <guid isPermaLink="true">http://example.com/posts/1</guid>
+				</item>
+			</channel>
+		</rss>
+	`))
+	have := feed.Items
+	want := []Item{
+        {
+            GUID:    "http://example.com/posts/1",
+            URL:     "http://example.com/posts/1",
+        },
+    }
+	for i := 0; i < len(want); i++ {
+		if want[i] != have[i] {
+			t.Errorf("Failed to handle isPermalink\nwant: %#v\nhave: %#v\n", want[i], have[i])
+		}
+	}
+}