Use localized date and time formats in interpolate_hash

lib/i18n/interpolate/ruby.rb

@@ -43,7 +43,13 @@ def interpolate_hash(string, values)
                     config.missing_interpolation_argument_handler.call(key, values, string)
                   end
           value = value.call(values) if value.respond_to?(:call)
-          $3 ? sprintf("%#{$3}", value) : value
+
+          # Localize interpolated Date's, Time's, and DateTime's
+          if value.respond_to?(:strftime)
+            backend.localize(locale, value)
+          else
+            $3 ? sprintf("%#{$3}", value) : value
+          end
         end
       end
 

lib/i18n/tests/interpolation.rb

@@ -107,6 +107,46 @@ module Interpolation
         end
       end
 
+      test "interpolation: given a Date with no default format set it raises I18n::MissingTranslationData" do
+        assert_raises(I18n::MissingTranslationData) do
+          date = Date.new(2008, 3, 1)
+          interpolate(:default => '%{date}', :date => date)
+        end
+      end
+
+      test "interpolation: given a Time with no default format set it raises I18n::MissingTranslationData" do
+        assert_raises(I18n::MissingTranslationData) do
+          time = Time.utc(2008, 3, 1, 6, 0)
+          interpolate(:default => '%{time}', :time => time)
+        end
+      end
+
+      test "interpolation: given a DateTime with no default format set it raises I18n::MissingTranslationData" do
+        assert_raises(I18n::MissingTranslationData) do
+          datetime = Time.utc(2008, 3, 1, 6, 0).to_datetime
+          interpolate(:default => '%{datetime}', :datetime => datetime)
+        end
+      end
+
+      test "interpolation: given a Date it localizes it to the default date format" do
+        setup_datetime_localizations
+        date = Date.new(2008, 3, 1)
+        assert_equal '01.03.2008', interpolate(:default => '%{date}', :date => date)
+      end
+
+      test "interpolation: given a Time it localizes it to the default time format" do
+        setup_datetime_localizations
+        time = Time.utc(2008, 3, 1, 6, 0)
+        assert_equal 'Sa, 01. Mär 2008 06:00:00 +0000', interpolate(:default => '%{time}', :time => time)
+      end
+
+      # DateTime uses the Time format
+      test "interpolation: given a DateTime it localizes it to the default time format" do
+        setup_datetime_localizations
+        datetime = Time.utc(2008, 3, 1, 6, 0).to_datetime
+        assert_equal 'Sa, 01. Mär 2008 06:00:00 +0000', interpolate(:default => '%{datetime}', :datetime => datetime)
+      end
+
       test "interpolation: given a translations containing a reserved key it raises I18n::ReservedInterpolationKey" do
         assert_raises(I18n::ReservedInterpolationKey) { interpolate(:foo => :bar, :default => '%{exception_handler}') }
         assert_raises(I18n::ReservedInterpolationKey) { interpolate(:foo => :bar, :default => '%{default}') }
@@ -158,6 +198,25 @@ def interpolate(*args)
         key = args.pop
         I18n.backend.translate('en', key, options)
       end
+
+      def setup_datetime_localizations
+        I18n.backend.store_translations :en, {
+          :date => {
+            :formats => {
+              :default => "%d.%m.%Y"
+            },
+            # :time format uses abbreviated day and month names
+            :abbr_day_names => %w(So Mo Di Mi Do Fr Sa),
+            :abbr_month_names => %w(Jan Feb Mär Apr Mai Jun Jul Aug Sep Okt Nov Dez).unshift(nil)
+          },
+
+          :time => {
+            :formats => {
+              :default => "%a, %d. %b %Y %H:%M:%S %z"
+            }
+          }
+        }
+      end
     end
   end
 end

lib/i18n/tests/localization/date.rb

@@ -22,6 +22,10 @@ def setup
           assert_equal '01.03.2008', I18n.l(@date, :format => :default, :locale => :de)
         end
 
+        test "localize Date: given no format it uses the default" do
+          assert_equal '01.03.2008', I18n.l(@date, :locale => :de)
+        end
+
         test "localize Date: given a day name format it returns the correct day name" do
           assert_equal 'Samstag', I18n.l(@date, :format => '%A', :locale => :de)
         end

lib/i18n/tests/localization/date_time.rb

@@ -23,6 +23,10 @@ def setup
           assert_equal 'Sa, 01. Mär 2008 06:00:00 +0000', I18n.l(@datetime, :format => :default, :locale => :de)
         end
 
+        test "localize DateTime: given no format it uses the default" do
+          assert_equal 'Sa, 01. Mär 2008 06:00:00 +0000', I18n.l(@datetime, :locale => :de)
+        end
+
         test "localize DateTime: given a day name format it returns the correct day name" do
           assert_equal 'Samstag', I18n.l(@datetime, :format => '%A', :locale => :de)
         end

lib/i18n/tests/localization/time.rb

@@ -19,10 +19,13 @@ def setup
           assert_equal '01. März 2008 06:00', I18n.l(@time, :format => :long, :locale => :de)
         end
 
-        # TODO Seems to break on Windows because ENV['TZ'] is ignored. What's a better way to do this?
-        # def test_localize_given_the_default_format_it_uses_it
-        #   assert_equal 'Sa, 01. Mar 2008 06:00:00 +0000', I18n.l(@time, :format => :default, :locale => :de)
-        # end
+        test "localize Time: given the default format it uses it" do
+          assert_equal 'Sa, 01. Mär 2008 06:00:00 +0000', I18n.l(@time, :format => :default, :locale => :de)
+        end
+
+        test "localize Time: given no format it uses the default" do
+          assert_equal 'Sa, 01. Mär 2008 06:00:00 +0000', I18n.l(@time, :locale => :de)
+        end
 
         test "localize Time: given a day name format it returns the correct day name" do
           assert_equal 'Samstag', I18n.l(@time, :format => '%A', :locale => :de)