Add tests for empty atx headings

Author: lggruspe

test/header-decrease.vader

@@ -115,3 +115,29 @@ Expect (hashtags are not affected):
   ## a
 
   #hashtag
+
+Given markdown;
+#
+
+##
+
+Execute (HeaderIncrease with empty atx headings):
+  :HeaderIncrease
+
+Expect (increase level of all headers):
+  ##
+
+  ###
+
+Given markdown;
+##
+
+###
+
+Execute (HeaderDecrease with empty atx headings):
+  :HeaderDecrease
+
+Expect (decrease level of all headers):
+  #
+
+  ##

test/map.vader

@@ -157,3 +157,23 @@ Execute (]h):
   AssertEqual line('.'), 3
   normal ]h
   AssertEqual line('.'), 1
+
+Given markdown;
+#
+
+##
+
+#
+
+##
+
+Execute (]] empty atx heading):
+  AssertEqual line('.'), 1
+  normal ]]
+  AssertEqual line('.'), 3
+  normal [[
+  AssertEqual line('.'), 1
+  normal ][
+  AssertEqual line('.'), 5
+  normal []
+  AssertEqual line('.'), 1