Makes wiki text formatter pluggable.

Original patch #2025 by Yuki Sonoda slightly edited.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@1955 e93f8b46-1217-0410-a6f0-8f06a7374b81

test/unit/helpers/application_helper_test.rb

@@ -350,6 +350,13 @@ EXPECTED
     assert textilizable(text).match(/Unknow project/)
   end
   
+  def test_default_formatter
+    Setting.text_formatting = 'unknown'
+    text = 'a *link*: http://www.example.net/'
+    assert_equal '<p>a *link*: <a href="http://www.example.net/">http://www.example.net/</a></p>', textilizable(text)
+    Setting.text_formatting = 'textile'
+  end
+  
   def test_date_format_default
     today = Date.today
     Setting.date_format = ''