Refactor AddImageTitle rewriter.

* Only processes images with `src` **and** `title` attributes (others are ignored).
* Processes **all** images in the document (not just the first one).
* Wraps the image and its title attribute in a `figure` tag with the title attribute's contents in a `figcaption` tag.

Updated xkcd rewriter unit test.

Added another xkcd rewriter unit test to check rendering of images without title tags.

reader/rewrite/rewrite_functions.go

@@ -22,9 +22,19 @@ func addImageTitle(entryURL, entryContent string) string {
 		return entryContent
 	}
 
-	imgTag := doc.Find("img").First()
-	if titleAttr, found := imgTag.Attr("title"); found {
-		return entryContent + `<blockquote cite="` + entryURL + `">` + titleAttr + "</blockquote>"
+	matches := doc.Find("img[src][title]")
+
+	if matches.Length() > 0 {
+		matches.Each(func(i int, img *goquery.Selection) {
+			altAttr := img.AttrOr("alt", "")
+			srcAttr, _ := img.Attr("src")
+			titleAttr, _ := img.Attr("title")
+
+			img.ReplaceWithHtml(`<figure><img src="` + srcAttr + `" alt="` + altAttr + `"/><figcaption><p>` + titleAttr + `</p></figcaption></figure>`)
+		})
+
+		output, _ := doc.Find("body").First().Html()
+		return output
 	}
 
 	return entryContent

reader/rewrite/rewriter_test.go

@@ -35,7 +35,15 @@ func TestRewriteWithInexistingCustomRule(t *testing.T) {
 func TestRewriteWithXkcdLink(t *testing.T) {
 	description := `<img src="https://imgs.xkcd.com/comics/thermostat.png" title="Your problem is so terrible, I worry that, if I help you, I risk drawing the attention of whatever god of technology inflicted it on you." alt="Your problem is so terrible, I worry that, if I help you, I risk drawing the attention of whatever god of technology inflicted it on you." />`
 	output := Rewriter("https://xkcd.com/1912/", description, ``)
-	expected := description + `<blockquote cite="https://xkcd.com/1912/">Your problem is so terrible, I worry that, if I help you, I risk drawing the attention of whatever god of technology inflicted it on you.</blockquote>`
+	expected := `<figure><img src="https://imgs.xkcd.com/comics/thermostat.png" alt="Your problem is so terrible, I worry that, if I help you, I risk drawing the attention of whatever god of technology inflicted it on you."/><figcaption><p>Your problem is so terrible, I worry that, if I help you, I risk drawing the attention of whatever god of technology inflicted it on you.</p></figcaption></figure>`
+	if expected != output {
+		t.Errorf(`Not expected output: got "%s" instead of "%s"`, output, expected)
+	}
+}
+func TestRewriteWithXkcdLinkAndImageNoTitle(t *testing.T) {
+	description := `<img src="https://imgs.xkcd.com/comics/thermostat.png" alt="Your problem is so terrible, I worry that, if I help you, I risk drawing the attention of whatever god of technology inflicted it on you." />`
+	output := Rewriter("https://xkcd.com/1912/", description, ``)
+	expected := description
 	if expected != output {
 		t.Errorf(`Not expected output: got "%s" instead of "%s"`, output, expected)
 	}