+Given markdown;
+# h1 space
+
+#h1 nospace
+
+# h1 2 spaces
+
+# h1 trailing hash #
+
+## h2 space
+
+##h2 nospace
+
+## h2 trailing hash ##
+
+### h3 space
+
+###h3 nospace
+
+### h3 trailing hash ###
+
+#### h4
+
+##### h5
+
+###### h6
+
+Execute (atx headers):
+ AssertEqual SyntaxOf('# h1 space'), 'htmlH1'
+ AssertEqual SyntaxOf('#h1 nospace'), 'htmlH1'
+ AssertEqual SyntaxOf('# h1 2 spaces'), 'htmlH1'
+ AssertEqual SyntaxOf('# h1 trailing hash #'), 'htmlH1'
+ AssertEqual SyntaxOf('## h2 space'), 'htmlH2'
+ AssertEqual SyntaxOf('##h2 nospace'), 'htmlH2'
+ AssertEqual SyntaxOf('## h2 trailing hash ##'), 'htmlH2'
+ AssertEqual SyntaxOf('### h3 space'), 'htmlH3'
+ AssertEqual SyntaxOf('###h3 nospace'), 'htmlH3'
+ AssertEqual SyntaxOf('### h3 trailing hash ###'), 'htmlH3'
+ AssertEqual SyntaxOf('#### h4'), 'htmlH4'
+ AssertEqual SyntaxOf('##### h5'), 'htmlH5'
+ AssertEqual SyntaxOf('###### h6'), 'htmlH6'
+
+Given markdown;
+# h1 before h2
+
+## h2 between h1s
+
+# h1 after h2
+
+Execute (atx headers relative positions):
+ AssertEqual SyntaxOf('# h1 before h2'), 'htmlH1'
+ AssertEqual SyntaxOf('## h2 between h1s'), 'htmlH2'
+ AssertEqual SyntaxOf('# h1 after h2'), 'htmlH1'
+
+Given markdown;
+setex h1
+========
+
+setex h2
+--------
+
+setex h1 single punctuation
+=
+
+setex h1 punctuation longer than header
+================================
+
+Execute (setex headers):
+ AssertEqual SyntaxOf('setex h1'), 'htmlH1'
+ AssertEqual SyntaxOf('^========$'), 'htmlH1'
+ AssertEqual SyntaxOf('setex h2'), 'htmlH2'
+ AssertEqual SyntaxOf('--------'), 'htmlH2'
+ AssertEqual SyntaxOf('setex h1 single punctuation'), 'htmlH1'
+ AssertEqual SyntaxOf('^=$'), 'htmlH1'
+ AssertEqual SyntaxOf('setex h1 punctuation longer than header'), 'htmlH1'
+ AssertEqual SyntaxOf('^================================$'), 'htmlH1'
+
+Given markdown;
+- not Setex
+- because list
+
+Execute (prevent list vs Setex confusion):
+ AssertNotEqual SyntaxOf('- not Setex'), 'htmlH2'
+ AssertNotEqual SyntaxOf('- becuase list'), 'htmlH2'
+
+Given markdown;
+setex h1 before atx
+===================
+
+## atx h2
+
+### atx h3
+
+# atx h1
+
+setex h2
+------------------
+
+### atx h3 2
+
+Execute (mixed atx and setex headers):
+ AssertEqual SyntaxOf('setex h1 before atx'), 'htmlH1'
+ AssertEqual SyntaxOf('==================='), 'htmlH1'
+ AssertEqual SyntaxOf('## atx h2'), 'htmlH2'
+ AssertEqual SyntaxOf('### atx h3'), 'htmlH3'
+ AssertEqual SyntaxOf('# atx h1'), 'htmlH1'
+ AssertEqual SyntaxOf('setex h2'), 'htmlH2'
+ AssertEqual SyntaxOf('------------------'), 'htmlH2'
+