Add test to prevent regression

test/data/fenced_code_block.html

@@ -15,4 +15,6 @@ still a fenced code block</code></pre>
 <pre><code>foo
 
 
-bar</code></pre>
+bar</code></pre>
+<pre><code class="language-php">&lt;?php
+echo "Hello World";</code></pre>

test/data/fenced_code_block.md

@@ -35,4 +35,9 @@ foo
 
 
 bar
+```
+
+```php some-class
+<?php
+echo "Hello World";
 ```