strip_tags returns nil for a blank arg such as nil or "". Closes #2229.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4916 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

actionpack/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* strip_tags returns nil for a blank arg such as nil or "".  #2229 [duncan@whomwah.com]
+
 * Cleanup assert_tag :children counting.  #2181 [jamie@bravenet.com]
 
 * button_to accepts :method so you can PUT and DELETE with it.  #6005 [Dan Webb]

actionpack/lib/action_view/helpers/text_helper.rb

@@ -213,7 +213,8 @@ module ActionView
       # tokenizer and so it's HTML parsing ability is limited by that of html-scanner.
       #
       # Returns the tag free text.
-      def strip_tags(html)
+      def strip_tags(html)     
+        return nil if html.blank?
         if html.index("<")
           text = ""
           tokenizer = HTML::Tokenizer.new(html)

actionpack/test/template/text_helper_test.rb

@@ -314,7 +314,7 @@ class TextHelperTest < Test::Unit::TestCase
     assert_equal(
     %{This is a test.\n\n\nIt no longer contains any HTML.\n}, strip_tags(
     %{<title>This is <b>a <a href="" target="_blank">test</a></b>.</title>\n\n<!-- it has a comment -->\n\n<p>It no <b>longer <strong>contains <em>any <strike>HTML</strike></em>.</strong></b></p>\n}))
-    assert_equal("This has a  here.", strip_tags("This has a <!-- comment --> here."))
+    assert_equal "This has a  here.", strip_tags("This has a <!-- comment --> here.")
+    [nil, '', '   '].each { |blank| assert_nil strip_tags(blank) }
   end
-
 end