Improve test coverage of Duration. Closes #7182 [richcollins]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@6007 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/test/core_ext/duration_test.rb

@@ -14,4 +14,8 @@ def test_inspect
   def test_minus_with_duration_does_not_break_subtraction_of_date_from_date
     assert_nothing_raised { Date.today - Date.today }
   end
+  
+  def test_plus_with_time
+    assert_equal 1 + 1.second, 1.second + 1, "Duration + Numeric should == Numeric + Duration"
+  end
 end