Time durations use since instead of + for accuracy. Closes #8513.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@6901 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

2 files changed, 2 insertions, 2 deletions

diff --git a/activesupport/lib/active_support/core_ext/date_time/calculations.rb b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
index dd30dd07bc..3e62891fcf 100644
--- a/activesupport/lib/active_support/core_ext/date_time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
@@ -45,7 +45,7 @@ module ActiveSupport #:nodoc:
         # Returns a new DateTime representing the time a number of seconds since the instance time
         # Do not use this method in combination with x.months, use months_since instead!
         def since(seconds)
-          self + Rational(seconds, 86400)
+          self + Rational(seconds.round, 86400)
         end
         alias :in :since
 
diff --git a/activesupport/lib/active_support/duration.rb b/activesupport/lib/active_support/duration.rb
index 5279c4435a..721bc18795 100644
--- a/activesupport/lib/active_support/duration.rb
+++ b/activesupport/lib/active_support/duration.rb
@@ -67,7 +67,7 @@ module ActiveSupport
       parts.inject(time) do |t,(type,number)|
         if t.acts_like?(:time)
           if type == :seconds
-            t + (sign * number)
+            t.since(sign * number)
           else
             t.advance(type => sign * number)
           end