fixes #786 where timezone handling of RoR screwed the algorithm to find the last sunday of march in 2009

Fix is a bit of a hack, see #786 for futher explanation.

app/controllers/application.rb

@@ -170,11 +170,12 @@ class ApplicationController < ActionController::Base
     # set dates
     todo.recurring_todo_id = rt.id
     todo.due = rt.get_due_date(date)
-    # make sure that show_from is not in the past
+    
     show_from_date = rt.get_show_from_date(date)
     if show_from_date.nil?
       todo.show_from=nil
     else
+      # make sure that show_from is not in the past
       todo.show_from = show_from_date < Time.zone.now ? nil : show_from_date
     end
     

app/models/recurring_todo.rb

@@ -495,12 +495,14 @@ class RecurringTodo < ActiveRecord::Base
   
   def get_xth_day_of_month(x, weekday, month, year)
     if x == 5
-      # last -> count backwards
-      last_day = Time.zone.local(year, month, Time.days_in_month(month))
+      # last -> count backwards. use UTC to avoid strange timezone oddities
+      # where last_day -= 1.day seems to shift tz+0100 to tz+0000
+      last_day = Time.utc(year, month, Time.days_in_month(month))
       while last_day.wday != weekday
         last_day -= 1.day
       end
-      return last_day
+      # convert back to local timezone
+      return Time.zone.local(last_day.year, last_day.month, last_day.day)
     else
       # 1-4th -> count upwards
       start = Time.zone.local(year,month,1)
@@ -524,7 +526,8 @@ class RecurringTodo < ActiveRecord::Base
     case self.recurrence_selector
     when 0 # specific day of a specific month
       if start.month > month || (start.month == month && start.day >= day)
-        # if there is no next month n and day m in this year, search in next year
+        # if there is no next month n and day m in this year, search in next
+        # year
         start = Time.zone.local(start.year+1, month, 1) 
       else
         # if there is a next month n, stay in this year

test/functional/recurring_todos_controller_test.rb

@@ -79,7 +79,7 @@ class RecurringTodosControllerTest < ActionController::TestCase
     recurring_todo_1 = RecurringTodo.find(1)
     assert recurring_todo_1.completed?
     
-    # remove remaining todo 
+    # remove remaining todo
     todo = Todo.find_by_recurring_todo_id(1)
     todo.recurring_todo_id = 2
     todo.save
@@ -124,5 +124,60 @@ class RecurringTodosControllerTest < ActionController::TestCase
     # show_from should be nil since now+4.days-10.days is in the past
     assert_equal nil, new_todo.show_from
   end
+  
+  def test_last_sunday_of_march
+    # this test is a duplicate of the unit test. Only this test covers the
+    # codepath in the controllers
+    
+    login_as(:admin_user)
+
+    orig_rt_count = RecurringTodo.count
+    orig_todo_count = Todo.count
+
+    put :create,       
+      "context_name"=>"library", 
+      "project_name"=>"Build a working time machine", 
+      "recurring_todo" => 
+      {
+      "daily_every_x_days"=>"1", 
+      "daily_selector"=>"daily_every_x_day", 
+      "description"=>"new recurring pattern", 
+      "end_date" => "",
+      "ends_on" => "no_end_date",
+      "monthly_day_of_week" => "1",
+      "monthly_every_x_day" => "22",
+      "monthly_every_x_month2" => "1",
+      "monthly_every_x_month" => "1",
+      "monthly_every_xth_day"=>"1",
+      "monthly_selector"=>"monthly_every_x_day",
+      "notes"=>"with some notes",
+      "number_of_occurences" => "",
+      "recurring_period"=>"yearly",
+      "recurring_show_days_before"=>"0",
+      "recurring_target"=>"due_date",
+      "start_from"=>"",
+      "weekly_every_x_week"=>"1",
+      "weekly_return_monday"=>"w",
+      "yearly_day_of_week"=>"0",
+      "yearly_every_x_day"=>"22",
+      "yearly_every_xth_day"=>"5",
+      "yearly_month_of_year2"=>"3",
+      "yearly_month_of_year"=>"10",
+      "yearly_selector"=>"yearly_every_xth_day"
+    }, 
+      "tag_list"=>"one, two, three, four"
+    
+    # check new recurring todo added
+    assert_equal orig_rt_count+1, RecurringTodo.count  
+    # check new todo added
+    assert_equal orig_todo_count+1, Todo.count
+
+    # find the newly created todo
+    new_todo = Todo.find_by_description("new recurring pattern")
+    assert !new_todo.nil?
+    
+    # the date should be 29 march 2009
+    assert_equal Time.zone.local(2009,3,29), new_todo.due
+  end
     
 end

test/unit/recurring_todo_test.rb

@@ -197,6 +197,15 @@ class RecurringTodoTest < Test::Rails::TestCase
     assert_equal due_date1, due_date2
   end
 
+  def test_last_sunday_of_march
+    @yearly.recurrence_selector = 1
+    @yearly.every_other2 = 3 # march
+    @yearly.every_other3 = 5 # last
+    @yearly.every_count = 0 # sunday
+    due_date = @yearly.get_due_date(Time.zone.local(2008,10,1)) # oct 1st
+    assert_equal Time.zone.local(2009,3,29), due_date # march 29th
+  end
+
   def test_start_from_in_future
     # every_day should return start_day if it is in the future
     @every_day.start_from = @in_three_days