TimeWithZone instances correctly enforce DST rules. Adding TimeZone#period_for_utc

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@9006 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/CHANGELOG

 *SVN*
 
+* TimeWithZone instances correctly enforce DST rules. Adding TimeZone#period_for_utc [Geoff Buesing]
+
 * test_time_with_datetime_fallback expects DateTime.local_offset instead of DateTime.now.offset [Geoff Buesing]
 
 * Adding TimeWithZone #marshal_dump and #marshal_load [Geoff Buesing]

activesupport/lib/active_support/time_with_zone.rb

@@ -27,7 +27,7 @@ def utc
   
     # Returns the underlying TZInfo::TimezonePeriod for the local time
     def period
-      @period ||= get_period_for_local
+      @period ||= time_zone.period_for_utc(utc)
     end
 
     # Returns the simultaneous time in the specified zone
@@ -150,6 +150,15 @@ def -(other)
       end
     end
     
+    %w(asctime day hour min mon sec usec wday yday year).each do |name|
+      define_method(name) do
+        time.__send__(name)
+      end
+    end
+    alias_method :ctime, :asctime
+    alias_method :mday, :day
+    alias_method :month, :mon
+    
     def to_a
       time.to_a[0, 8].push(dst?, zone)
     end
@@ -206,20 +215,9 @@ def respond_to?(sym)
   
     # Send the missing method to time instance, and wrap result in a new TimeWithZone with the existing time_zone
     def method_missing(sym, *args, &block)
-      result = time.__send__(sym, *args, &block)
-      result = result.change_time_zone(time_zone) if result.acts_like?(:time)
+      result = utc.__send__(sym, *args, &block)
+      result = result.in_time_zone(time_zone) if result.acts_like?(:time)
       result
     end
-  
-    private
-      def get_period_for_local
-        t = time
-        begin
-          time_zone.period_for_local(t, true)
-        rescue ::TZInfo::PeriodNotFound # failover logic from TzTime
-          t -= 1.hour
-          retry
-        end
-      end
   end
 end

activesupport/lib/active_support/values/time_zone.rb

@@ -211,6 +211,11 @@ def local_to_utc(time, dst=true)
       tzinfo.local_to_utc(time, dst)
     end
 
+    # Available so that TimeZone instances respond like TZInfo::Timezone instances
+    def period_for_utc(time)
+      tzinfo.period_for_utc(time)
+    end
+
     # Available so that TimeZone instances respond like TZInfo::Timezone instances
     def period_for_local(time, dst=true)
       tzinfo.period_for_local(time, dst)

activesupport/test/core_ext/time_with_zone_test.rb

@@ -165,6 +165,38 @@ def test_minus_with_time_with_zone
       assert_equal  86_400.0,  twz2 - twz1
     end
     
+    def test_plus_and_minus_enforce_spring_dst_rules
+      utc = Time.utc(2006,4,2,6,59,59) # == Apr 2 2006 01:59:59 EST; i.e., 1 second before daylight savings start
+      twz = ActiveSupport::TimeWithZone.new(utc, @time_zone)
+      assert_equal Time.utc(2006,4,2,1,59,59), twz.time
+      assert_equal false, twz.dst?
+      assert_equal 'EST', twz.zone
+      twz = twz + 1
+      assert_equal Time.utc(2006,4,2,3), twz.time # adding 1 sec springs forward to 3:00AM EDT
+      assert_equal true, twz.dst?
+      assert_equal 'EDT', twz.zone
+      twz = twz - 1 # subtracting 1 second takes goes back to 1:59:59AM EST
+      assert_equal Time.utc(2006,4,2,1,59,59), twz.time
+      assert_equal false, twz.dst?
+      assert_equal 'EST', twz.zone
+    end
+    
+    def test_plus_and_minus_enforce_fall_dst_rules
+      utc = Time.utc(2006,10,29,5,59,59) # == Oct 29 2006 01:59:59 EST; i.e., 1 second before daylight savings end
+      twz = ActiveSupport::TimeWithZone.new(utc, @time_zone)
+      assert_equal Time.utc(2006,10,29,1,59,59), twz.time
+      assert_equal true, twz.dst?
+      assert_equal 'EDT', twz.zone
+      twz = twz + 1
+      assert_equal Time.utc(2006,10,29,1), twz.time # adding 1 sec falls back from 1:59:59 EDT to 1:00AM EST
+      assert_equal false, twz.dst?
+      assert_equal 'EST', twz.zone
+      twz = twz - 1
+      assert_equal Time.utc(2006,10,29,1,59,59), twz.time # subtracting 1 sec goes back to 1:59:59AM EDT
+      assert_equal true, twz.dst?
+      assert_equal 'EDT', twz.zone
+    end
+    
     def test_to_a
       assert_equal [45, 30, 5, 1, 2, 2000, 2, 32, false, "HST"], ActiveSupport::TimeWithZone.new( Time.utc(2000, 2, 1, 15, 30, 45), TimeZone['Hawaii'] ).to_a
     end
@@ -219,9 +251,14 @@ def test_marshal_dump_and_load
     end
       
     def test_method_missing_with_non_time_return_value
-      assert_equal 1999, @twz.year
-      assert_equal 12, @twz.month
-      assert_equal 31, @twz.day
+      twz = ActiveSupport::TimeWithZone.new(Time.utc(1999,12,31,19,18,17,500), @time_zone)
+      assert_equal 1999, twz.year
+      assert_equal 12, twz.month
+      assert_equal 31, twz.day
+      assert_equal 14, twz.hour
+      assert_equal 18, twz.min
+      assert_equal 17, twz.sec
+      assert_equal 500, twz.usec
     end
   end