Time#xmlschema is only available when you've required 'time'. Add a unit test...

Time#xmlschema is only available when you've required 'time'.  Add a unit test to catch regressions. [Koz]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3880 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/lib/active_support/core_ext/time/conversions.rb

 require 'date'
+require 'time'
 
 module ActiveSupport #:nodoc:
   module CoreExtensions #:nodoc:

activesupport/test/core_ext/time_ext_test.rb

@@ -188,4 +188,8 @@ def test_next_month_on_31st
   def test_last_month_on_31st
     assert_equal Time.local(2004, 2, 29), Time.local(2004, 3, 31).last_month
   end
+  
+  def test_xmlschema_is_available
+    assert_nothing_raised { Time.now.xmlschema }
+  end
 end