fix(renderer): do not highlight syntax when language is not set (#515)

fixes #514

Signed-off-by: Xavier Coulon <[email protected]>

pkg/renderer/html5/delimited_block.go

@@ -236,7 +236,7 @@ func renderSourceBlock(ctx renderer.Context, b types.DelimitedBlock) ([]byte, er
 	language := b.Attributes.GetAsString(types.AttrLanguage)
 
 	hightligher, _ := ctx.Document.Attributes.GetAsString("source-highlighter")
-	if hightligher == "pygments" {
+	if language != "" && hightligher == "pygments" {
 		// using github.com/alecthomas/chroma to highlight the content
 		contentBuf = bytes.NewBuffer(nil)
 		lexer := lexers.Get(language)

pkg/renderer/html5/delimited_block_test.go

@@ -862,6 +862,25 @@ type Foo struct{
 			Expect(RenderHTML5Body(source)).To(Equal(expected))
 		})
 
+		It("should render source block without highlighter when language is not set", func() {
+			source := `:source-highlighter: pygments
+	
+[source]
+----
+type Foo struct{
+	Field string
+}
+----`
+			expected := `<div class="listingblock">
+<div class="content">
+<pre class="pygments highlight"><code>type Foo struct{
+	Field string
+}</code></pre>
+</div>
+</div>`
+			Expect(RenderHTML5Body(source)).To(Equal(expected))
+		})
+
 		It("should render source block with go syntax and custom style", func() {
 			source := `:source-highlighter: pygments
 :pygments-style: manni