Occurrences in DST start/end hour shouldn't be skipped

Fixes ice-cube-ruby#150

lib/ice_cube/time_util.rb

@@ -196,6 +196,13 @@ def self.days_in_n_months(time, month_distance)
       ((date >> month_distance) - date).to_i
     end
 
+    def self.dst_change(time)
+      one_hour_ago = time - ONE_HOUR
+      if time.dst? ^ one_hour_ago.dst?
+        (time.utc_offset - one_hour_ago.utc_offset) / ONE_HOUR
+      end
+    end
+
     # A utility class for safely moving time around
     class TimeWrapper
 

lib/ice_cube/validations/lock.rb

@@ -5,7 +5,7 @@ module IceCube
 
   module Validations::Lock
 
-    INTERVALS = {:hour => 24, :min => 60, :sec => 60, :month => 12, :wday => 7}
+    INTERVALS = {:min => 60, :sec => 60, :month => 12, :wday => 7}
 
     def validate(time, schedule)
       return send(:"validate_#{type}_lock", time, schedule) unless INTERVALS[type]
@@ -16,6 +16,23 @@ def validate(time, schedule)
 
     private
 
+    # Lock the hour if explicitly set by hour_of_day, but allow for the nearest
+    # hour during DST start to keep the correct interval.
+    #
+    def validate_hour_lock(time, schedule)
+      hour = value || schedule.start_time.send(type)
+      hour = 24 + hour if hour < 0
+      if hour >= time.hour
+        hour - time.hour
+      else
+        if dst_offset = TimeUtil.dst_change(time)
+          hour - time.hour + dst_offset
+        else
+          24 - time.hour + hour
+        end
+      end
+    end
+
     # For monthly rules that have no specified day value, the validation relies
     # on the schedule start time and jumps to include every month even if it
     # has fewer days than the schedule's start day.

lib/ice_cube/validations/schedule_lock.rb

@@ -34,6 +34,12 @@ def build_ical(builder)
       def build_hash(builder)
       end
 
+      def dst_adjust?
+        case @type
+        when :sec, :min then false
+        else true
+        end
+      end
     end
 
   end