improve tests

tests/data/atx_heading.html

@@ -5,3 +5,4 @@
 <h5>h5</h5>
 <h6>h6</h6>
 <h1>closed h1</h1>
+<p>#</p>

tests/data/atx_heading.md

@@ -11,3 +11,5 @@
 ###### h6
 
 # closed h1 #
+
+#

tests/data/tab-indented_code_block.html

@@ -0,0 +1,6 @@
+<pre><code>&lt;?php
+
+$message = 'Hello World!'; 
+echo $message;
+
+echo "following a blank line";</code></pre>

tests/data/tab-indented_code_block.md

@@ -0,0 +1,6 @@
+	<?php
+	
+	$message = 'Hello World!'; 
+	echo $message;
+
+	echo "following a blank line";