Make distance_of_time_in_words work with DateTime offsets

Because DateTime#to_time returns self when it has a non-zero offset
and subtracting two DateTime instances returns a Rational then the
distance_of_time_in_words methods outputs an incorrect value.

This is fixed in master because we can rely on Ruby 1.9.3's
implementation of to_time but it can't be fixed on Ruby 1.8.7 as
there is no way to map the DateTime to a Time with a non-zero offset.

We can workaround the problem by casting to Float before doing
the subtraction in the distance_of_time_in_words method.

Closes #8390

1 files changed, 10 insertions, 0 deletions

diff --git a/actionpack/test/template/date_helper_test.rb b/actionpack/test/template/date_helper_test.rb
index dd0aad7119..e4f84f8dd7 100644
--- a/actionpack/test/template/date_helper_test.rb
+++ b/actionpack/test/template/date_helper_test.rb
@@ -151,6 +151,16 @@ class DateHelperTest < ActionView::TestCase
     assert_equal "1 minute", distance_of_time_in_words(60.seconds, 0, true)
   end
 
+  def test_distance_in_words_with_offset_datetimes
+    start_date = DateTime.new 1975, 1, 31, 0, 0, 0, '+6'
+    end_date = DateTime.new 1977, 1, 31, 0, 0, 0, '+6'
+    assert_equal("about 2 years", distance_of_time_in_words(start_date, end_date))
+
+    start_date = DateTime.new 1982, 12, 3, 0, 0, 0, '+6'
+    end_date = DateTime.new 2010, 11, 30, 0, 0, 0, '+6'
+    assert_equal("almost 28 years", distance_of_time_in_words(start_date, end_date))
+  end
+
   def test_time_ago_in_words
     assert_equal "about 1 year", time_ago_in_words(1.year.ago - 1.day)
   end