Add failing test cases to be fixed

test/data/setext_header_spaces.html

@@ -0,0 +1,12 @@
+<h1>trailing space</h1>
+<h2>trailing space</h2>
+<h1>leading and trailing space</h1>
+<h2>leading and trailing space</h2>
+<h1>1 leading space</h1>
+<h2>1 leading space</h2>
+<h1>3 leading spaces</h1>
+<h2>3 leading spaces</h2>
+<p>too many leading spaces
+==</p>
+<p>too many leading spaces
+--</p>

test/data/setext_header_spaces.md

@@ -0,0 +1,29 @@
+trailing space
+== 
+
+trailing space
+-- 
+
+leading and trailing space
+ == 
+
+leading and trailing space
+ -- 
+
+1 leading space
+ ==
+
+1 leading space
+ --
+
+3 leading spaces
+   ==
+
+3 leading spaces
+   --
+
+too many leading spaces
+    ==
+
+too many leading spaces
+    --