Replace non-dst-aware TimeZone class with dst-aware class from tzinfo_timezone plugin. TimeZone#adjust and #unadjust are no longer available; tzinfo gem must now be present in order to perform time zone calculations, via #local_to_utc and #utc_to_local methods.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8679 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

4 files changed, 314 insertions, 125 deletions

diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index 5cd4a483e4..53ae421131 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Replace non-dst-aware TimeZone class with dst-aware class from tzinfo_timezone plugin. TimeZone#adjust and #unadjust are no longer available; tzinfo gem must now be present in order to perform time zone calculations, via #local_to_utc and #utc_to_local methods. [Geoff Buesing]
+
 * Extract ActiveSupport::Callbacks from Active Record, test case setup and teardown, and ActionController::Dispatcher.  #10727 [Josh Peek]
 
 * Introducing DateTime #utc, #utc? and #utc_offset, for duck-typing compatibility with Time. Closes #10002 [Geoff Buesing]
diff --git a/activesupport/lib/active_support/values/time_zone.rb b/activesupport/lib/active_support/values/time_zone.rb
index 09896c0aee..92d6febda3 100644
--- a/activesupport/lib/active_support/values/time_zone.rb
+++ b/activesupport/lib/active_support/values/time_zone.rb
@@ -1,20 +1,155 @@
-# A value object representing a time zone. A time zone is simply a named
-# offset (in seconds) from GMT. Note that two time zone objects are only
-# equivalent if they have both the same offset, and the same name.
-#
-# A TimeZone instance may be used to convert a Time value to the corresponding
-# time zone.
-#
-# The class also includes #all, which returns a list of all TimeZone objects.
 class TimeZone
-  include Comparable
+  MAPPING = {
+    "International Date Line West" => "Pacific/Midway",
+    "Midway Island"                => "Pacific/Midway",
+    "Samoa"                        => "Pacific/Pago_Pago",
+    "Hawaii"                       => "Pacific/Honolulu",
+    "Alaska"                       => "America/Juneau",
+    "Pacific Time (US & Canada)"   => "America/Los_Angeles",
+    "Tijuana"                      => "America/Tijuana",
+    "Mountain Time (US & Canada)"  => "America/Denver",
+    "Arizona"                      => "America/Phoenix",
+    "Chihuahua"                    => "America/Chihuahua",
+    "Mazatlan"                     => "America/Mazatlan",
+    "Central Time (US & Canada)"   => "America/Chicago",
+    "Saskatchewan"                 => "America/Regina",
+    "Guadalajara"                  => "America/Mexico_City",
+    "Mexico City"                  => "America/Mexico_City",
+    "Monterrey"                    => "America/Monterrey",
+    "Central America"              => "America/Guatemala",
+    "Eastern Time (US & Canada)"   => "America/New_York",
+    "Indiana (East)"               => "America/Indiana/Indianapolis",
+    "Bogota"                       => "America/Bogota",
+    "Lima"                         => "America/Lima",
+    "Quito"                        => "America/Lima",
+    "Atlantic Time (Canada)"       => "America/Halifax",
+    "Caracas"                      => "America/Caracas",
+    "La Paz"                       => "America/La_Paz",
+    "Santiago"                     => "America/Santiago",
+    "Newfoundland"                 => "America/St_Johns",
+    "Brasilia"                     => "America/Argentina/Buenos_Aires",
+    "Buenos Aires"                 => "America/Argentina/Buenos_Aires",
+    "Georgetown"                   => "America/Argentina/San_Juan",
+    "Greenland"                    => "America/Godthab",
+    "Mid-Atlantic"                 => "Atlantic/South_Georgia",
+    "Azores"                       => "Atlantic/Azores",
+    "Cape Verde Is."               => "Atlantic/Cape_Verde",
+    "Dublin"                       => "Europe/Dublin",
+    "Edinburgh"                    => "Europe/Dublin",
+    "Lisbon"                       => "Europe/Lisbon",
+    "London"                       => "Europe/London",
+    "Casablanca"                   => "Africa/Casablanca",
+    "Monrovia"                     => "Africa/Monrovia",
+    "Belgrade"                     => "Europe/Belgrade",
+    "Bratislava"                   => "Europe/Bratislava",
+    "Budapest"                     => "Europe/Budapest",
+    "Ljubljana"                    => "Europe/Ljubljana",
+    "Prague"                       => "Europe/Prague",
+    "Sarajevo"                     => "Europe/Sarajevo",
+    "Skopje"                       => "Europe/Skopje",
+    "Warsaw"                       => "Europe/Warsaw",
+    "Zagreb"                       => "Europe/Zagreb",
+    "Brussels"                     => "Europe/Brussels",
+    "Copenhagen"                   => "Europe/Copenhagen",
+    "Madrid"                       => "Europe/Madrid",
+    "Paris"                        => "Europe/Paris",
+    "Amsterdam"                    => "Europe/Amsterdam",
+    "Berlin"                       => "Europe/Berlin",
+    "Bern"                         => "Europe/Berlin",
+    "Rome"                         => "Europe/Rome",
+    "Stockholm"                    => "Europe/Stockholm",
+    "Vienna"                       => "Europe/Vienna",
+    "West Central Africa"          => "Africa/Algiers",
+    "Bucharest"                    => "Europe/Bucharest",
+    "Cairo"                        => "Africa/Cairo",
+    "Helsinki"                     => "Europe/Helsinki",
+    "Kyev"                         => "Europe/Kiev",
+    "Riga"                         => "Europe/Riga",
+    "Sofia"                        => "Europe/Sofia",
+    "Tallinn"                      => "Europe/Tallinn",
+    "Vilnius"                      => "Europe/Vilnius",
+    "Athens"                       => "Europe/Athens",
+    "Istanbul"                     => "Europe/Istanbul",
+    "Minsk"                        => "Europe/Minsk",
+    "Jerusalem"                    => "Asia/Jerusalem",
+    "Harare"                       => "Africa/Harare",
+    "Pretoria"                     => "Africa/Johannesburg",
+    "Moscow"                       => "Europe/Moscow",
+    "St. Petersburg"               => "Europe/Moscow",
+    "Volgograd"                    => "Europe/Moscow",
+    "Kuwait"                       => "Asia/Kuwait",
+    "Riyadh"                       => "Asia/Riyadh",
+    "Nairobi"                      => "Africa/Nairobi",
+    "Baghdad"                      => "Asia/Baghdad",
+    "Tehran"                       => "Asia/Tehran",
+    "Abu Dhabi"                    => "Asia/Muscat",
+    "Muscat"                       => "Asia/Muscat",
+    "Baku"                         => "Asia/Baku",
+    "Tbilisi"                      => "Asia/Tbilisi",
+    "Yerevan"                      => "Asia/Yerevan",
+    "Kabul"                        => "Asia/Kabul",
+    "Ekaterinburg"                 => "Asia/Yekaterinburg",
+    "Islamabad"                    => "Asia/Karachi",
+    "Karachi"                      => "Asia/Karachi",
+    "Tashkent"                     => "Asia/Tashkent",
+    "Chennai"                      => "Asia/Calcutta",
+    "Kolkata"                      => "Asia/Calcutta",
+    "Mumbai"                       => "Asia/Calcutta",
+    "New Delhi"                    => "Asia/Calcutta",
+    "Kathmandu"                    => "Asia/Katmandu",
+    "Astana"                       => "Asia/Dhaka",
+    "Dhaka"                        => "Asia/Dhaka",
+    "Sri Jayawardenepura"          => "Asia/Dhaka",
+    "Almaty"                       => "Asia/Almaty",
+    "Novosibirsk"                  => "Asia/Novosibirsk",
+    "Rangoon"                      => "Asia/Rangoon",
+    "Bangkok"                      => "Asia/Bangkok",
+    "Hanoi"                        => "Asia/Bangkok",
+    "Jakarta"                      => "Asia/Jakarta",
+    "Krasnoyarsk"                  => "Asia/Krasnoyarsk",
+    "Beijing"                      => "Asia/Shanghai",
+    "Chongqing"                    => "Asia/Chongqing",
+    "Hong Kong"                    => "Asia/Hong_Kong",
+    "Urumqi"                       => "Asia/Urumqi",
+    "Kuala Lumpur"                 => "Asia/Kuala_Lumpur",
+    "Singapore"                    => "Asia/Singapore",
+    "Taipei"                       => "Asia/Taipei",
+    "Perth"                        => "Australia/Perth",
+    "Irkutsk"                      => "Asia/Irkutsk",
+    "Ulaan Bataar"                 => "Asia/Ulaanbaatar",
+    "Seoul"                        => "Asia/Seoul",
+    "Osaka"                        => "Asia/Tokyo",
+    "Sapporo"                      => "Asia/Tokyo",
+    "Tokyo"                        => "Asia/Tokyo",
+    "Yakutsk"                      => "Asia/Yakutsk",
+    "Darwin"                       => "Australia/Darwin",
+    "Adelaide"                     => "Australia/Adelaide",
+    "Canberra"                     => "Australia/Melbourne",
+    "Melbourne"                    => "Australia/Melbourne",
+    "Sydney"                       => "Australia/Sydney",
+    "Brisbane"                     => "Australia/Brisbane",
+    "Hobart"                       => "Australia/Hobart",
+    "Vladivostok"                  => "Asia/Vladivostok",
+    "Guam"                         => "Pacific/Guam",
+    "Port Moresby"                 => "Pacific/Port_Moresby",
+    "Magadan"                      => "Asia/Magadan",
+    "Solomon Is."                  => "Asia/Magadan",
+    "New Caledonia"                => "Pacific/Noumea",
+    "Fiji"                         => "Pacific/Fiji",
+    "Kamchatka"                    => "Asia/Kamchatka",
+    "Marshall Is."                 => "Pacific/Majuro",
+    "Auckland"                     => "Pacific/Auckland",
+    "Wellington"                   => "Pacific/Auckland",
+    "Nuku'alofa"                   => "Pacific/Tongatapu"
+  }
 
+  include Comparable
   attr_reader :name, :utc_offset
 
-  # Create a new TimeZone object with the given name and offset. The offset is
-  # the number of seconds that this time zone is offset from UTC (GMT). Seconds
-  # were chosen as the offset unit because that is the unit that Ruby uses
-  # to represent time zone offsets (see Time#utc_offset).
+  # Create a new TimeZone object with the given name and offset. The
+  # offset is the number of seconds that this time zone is offset from UTC
+  # (GMT). Seconds were chosen as the offset unit because that is the unit that
+  # Ruby uses to represent time zone offsets (see Time#utc_offset).
   def initialize(name, utc_offset)
     @name = name
     @utc_offset = utc_offset
@@ -24,35 +159,14 @@ class TimeZone
   # format "+HH:MM". If the offset is zero, this returns the empty
   # string. If +colon+ is false, a colon will not be inserted into the
   # result.
-  def formatted_offset( colon=true )
-    return "" if utc_offset == 0
-    utc_offset.to_utc_offset_s(colon)
-  end
-
-  # Compute and return the current time, in the time zone represented by
-  # +self+.
-  def now
-    adjust(Time.now)
-  end
-
-  # Return the current date in this time zone.
-  def today
-    now.to_date
+  def formatted_offset(colon=true)
+    utc_offset == 0 ? '' : offset(colon)
   end
-
-  # Adjust the given time to the time zone represented by +self+.
-  def adjust(time)
-    time = time.to_time unless time.is_a?(::Time)
-    time + utc_offset - time.utc_offset
-  end
-
-  # Reinterprets the given time value as a time in the current time
-  # zone, and then adjusts it to return the corresponding time in the
-  # local time zone.
-  def unadjust(time)
-    time = time.to_time unless time.is_a?(::Time)
-    time = time.localtime
-    time - utc_offset - time.utc_offset
+  
+  # Returns the offset of this time zone as a formatted string, of the
+  # format "+HH:MM".
+  def offset(colon=true)
+    utc_offset.to_utc_offset_s(colon)
   end
 
   # Compare this time zone to the parameter. The two are comapred first on
@@ -65,18 +179,58 @@ class TimeZone
 
   # Returns a textual representation of this time zone.
   def to_s
-    "(UTC#{formatted_offset}) #{name}"
+    "(GMT#{formatted_offset}) #{name}"
+  end
+
+  begin # the following methods depend on the tzinfo gem
+    require_library_or_gem "tzinfo" unless Object.const_defined?(:TZInfo)
+    
+    # Compute and return the current time, in the time zone represented by
+    # +self+.
+    def now
+      tzinfo.now
+    end
+
+    # Return the current date in this time zone.
+    def today
+      now.to_date
+    end
+
+    # Adjust the given time to the time zone represented by +self+.
+    def utc_to_local(time)
+      tzinfo.utc_to_local(time)
+    end
+
+    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_local(time, dst=true)
+      tzinfo.period_for_local(time, dst)
+    end
+    
+    def tzinfo
+      return @tzinfo if @tzinfo
+      @tzinfo = MAPPING[name]
+      if String === @tzinfo
+        @tzinfo = TZInfo::Timezone.get(@tzinfo)
+        MAPPING[name] = @tzinfo
+      end
+      @tzinfo
+    end
+    
+  rescue LoadError # Tzinfo gem is not available
+    # re-raise LoadError only when a tzinfo-dependent method is called:
+    %w(now today utc_to_local local_to_utc period_for_local tzinfo).each do |method|
+      define_method(method) {|*args| raise LoadError, "TZInfo gem is required for TimeZone##{method}. `gem install tzinfo` and try again."}
+    end
   end
 
   @@zones = nil
 
   class << self
-    # Create a new TimeZone instance with the given name and offset.
-    def create(name, offset)
-      zone = allocate
-      zone.send!(:initialize, name, offset)
-      zone
-    end
+    alias_method :create, :new
 
     # Return a TimeZone instance with the given name, or +nil+ if no
     # such TimeZone instance exists. (This exists to support the use of
@@ -85,18 +239,18 @@ class TimeZone
       self[name]
     end
 
-    # Return an array of all TimeZone objects. There are multiple TimeZone
-    # objects per time zone, in many cases, to make it easier for users to
-    # find their own time zone.
+    # Return an array of all TimeZone objects. There are multiple
+    # TimeZone objects per time zone, in many cases, to make it easier
+    # for users to find their own time zone.
     def all
       unless @@zones
         @@zones = []
-        [[-43_200, "International Date Line West" ],
-         [-39_600, "Midway Island", "Samoa" ],
+        @@zones_map = {}
+        [[-39_600, "International Date Line West", "Midway Island", "Samoa" ],
          [-36_000, "Hawaii" ],
          [-32_400, "Alaska" ],
          [-28_800, "Pacific Time (US & Canada)", "Tijuana" ],
-         [-25_200, "Mountain Time (US & Canada)", "Chihuahua", "Mazatlan", 
+         [-25_200, "Mountain Time (US & Canada)", "Chihuahua", "Mazatlan",
                    "Arizona" ],
          [-21_600, "Central Time (US & Canada)", "Saskatchewan", "Guadalajara",
                    "Mexico City", "Monterrey", "Central America" ],
@@ -141,7 +295,11 @@ class TimeZone
                    "Wellington" ],
          [ 46_800, "Nuku'alofa" ]].
         each do |offset, *places|
-          places.each { |place| @@zones << create(place, offset).freeze }
+          places.each do |place|
+            zone = create(place, offset)
+            @@zones << zone
+            @@zones_map[place] = zone
+          end
         end
         @@zones.sort!
       end
@@ -156,7 +314,8 @@ class TimeZone
     def [](arg)
       case arg
         when String
-          all.find { |z| z.name == arg }
+          all # force the zones to be loaded
+          @@zones_map[arg]
         when Numeric
           arg *= 3600 if arg.abs <= 13
           all.find { |z| z.utc_offset == arg.to_i }
@@ -167,7 +326,7 @@ class TimeZone
 
     # A regular expression that matches the names of all time zones in
     # the USA.
-    US_ZONES = /US|Arizona|Indiana|Hawaii|Alaska/ unless defined?(US_ZONES)
+    US_ZONES = /US|Arizona|Indiana|Hawaii|Alaska/
 
     # A convenience method for returning a collection of TimeZone objects
     # for time zones in the USA.
diff --git a/activesupport/test/abstract_unit.rb b/activesupport/test/abstract_unit.rb
index 2cfa245bc8..c2fd943ca0 100644
--- a/activesupport/test/abstract_unit.rb
+++ b/activesupport/test/abstract_unit.rb
@@ -4,15 +4,26 @@ $:.unshift "#{File.dirname(__FILE__)}/../lib"
 $:.unshift File.dirname(__FILE__)
 require 'active_support'
 
+def uses_gem(gem_name, test_name, version = '> 0')
+  require 'rubygems'
+  gem gem_name.to_s, version
+  require gem_name.to_s
+  yield
+rescue LoadError
+  $stderr.puts "Skipping #{test_name} tests. `gem install #{gem_name}` and try again."
+end
+
 # Wrap tests that use Mocha and skip if unavailable.
 unless defined? uses_mocha
-  def uses_mocha(test_name)
-    require 'rubygems'
-    gem 'mocha', '>= 0.5.5'
-    require 'mocha'
-    yield
-  rescue LoadError
-    $stderr.puts "Skipping #{test_name} tests. `gem install mocha` and try again."
+  def uses_mocha(test_name, &block)
+    uses_gem('mocha', test_name, '>= 0.5.5', &block)
+  end
+end
+
+# Wrap tests that use TZInfo and skip if unavailable.
+unless defined? uses_tzinfo
+  def uses_tzinfo(test_name, &block)
+    uses_gem('tzinfo', test_name, &block)
   end
 end
 
diff --git a/activesupport/test/time_zone_test.rb b/activesupport/test/time_zone_test.rb
index a974d85dd7..939d928b3e 100644
--- a/activesupport/test/time_zone_test.rb
+++ b/activesupport/test/time_zone_test.rb
@@ -1,94 +1,110 @@
 require 'abstract_unit'
 
 class TimeZoneTest < Test::Unit::TestCase
-  class MockTime
-    def self.now
-      Time.utc( 2004, 7, 25, 14, 49, 00 )
+  
+  uses_tzinfo 'TestTimeZoneCalculations' do
+    
+    def test_utc_to_local
+      silence_warnings do # silence warnings raised by tzinfo gem
+        zone = TimeZone['Eastern Time (US & Canada)']
+        assert_equal Time.utc(1999, 12, 31, 19), zone.utc_to_local(Time.utc(2000, 1)) # standard offset -0500
+        assert_equal Time.utc(2000, 6, 30, 20), zone.utc_to_local(Time.utc(2000, 7)) # dst offset -0400
+      end
     end
-
-    def self.local(*args)
-      Time.utc(*args)
+  
+    def test_local_to_utc
+      silence_warnings do # silence warnings raised by tzinfo gem
+        zone = TimeZone['Eastern Time (US & Canada)']
+        assert_equal Time.utc(2000, 1, 1, 5), zone.local_to_utc(Time.utc(2000, 1)) # standard offset -0500
+        assert_equal Time.utc(2000, 7, 1, 4), zone.local_to_utc(Time.utc(2000, 7)) # dst offset -0400
+      end
+    end
+    
+    def test_period_for_local
+      silence_warnings do # silence warnings raised by tzinfo gem
+        zone = TimeZone['Eastern Time (US & Canada)']
+        assert_instance_of TZInfo::TimezonePeriod, zone.period_for_local(Time.utc(2000))
+      end
+    end
+    
+    TimeZone::MAPPING.keys.each do |name|
+      define_method("test_map_#{name.downcase.gsub(/[^a-z]/, '_')}_to_tzinfo") do
+        silence_warnings do # silence warnings raised by tzinfo gem
+          zone = TimeZone[name]
+          assert zone.tzinfo.respond_to?(:period_for_local)
+        end
+      end
     end
-  end
 
-  TimeZone::Time = MockTime
+    TimeZone.all.each do |zone|
+      name = zone.name.downcase.gsub(/[^a-z]/, '_')
+      define_method("test_from_#{name}_to_map") do
+        silence_warnings do # silence warnings raised by tzinfo gem
+          assert_instance_of TimeZone, TimeZone[zone.name]
+        end
+      end
+
+      define_method("test_utc_offset_for_#{name}") do
+        silence_warnings do # silence warnings raised by tzinfo gem
+          period = zone.tzinfo.period_for_utc(Time.utc(2006,1,1,0,0,0))
+          assert_equal period.utc_offset, zone.utc_offset
+        end
+      end
+    end
 
+    uses_mocha 'TestTimeZoneNowAndToday' do
+      def test_now
+        TZInfo::DataTimezone.any_instance.stubs(:now).returns(Time.utc(2000))
+        assert_equal Time.utc(2000), TimeZone['Eastern Time (US & Canada)'].now
+      end
+    
+      def test_today
+        TZInfo::DataTimezone.any_instance.stubs(:now).returns(Time.utc(2000))
+        assert_equal Date.new(2000), TimeZone['Eastern Time (US & Canada)'].today
+      end
+    end
+  end
+  
   def test_formatted_offset_positive
-    zone = TimeZone.create( "Test", 4200 )
-    assert_equal "+01:10", zone.formatted_offset
+    zone = TimeZone['Moscow']
+    assert_equal "+03:00", zone.formatted_offset
+    assert_equal "+0300", zone.formatted_offset(false)
   end
-
+  
   def test_formatted_offset_negative
-    zone = TimeZone.create( "Test", -4200 )
-    assert_equal "-01:10", zone.formatted_offset
-  end
-
-  def test_now
-    zone = TimeZone.create( "Test", 4200 )
-    assert_equal Time.local(2004,7,25,15,59,00).to_a[0,6], zone.now.to_a[0,6]
-  end
-
-  def test_today
-    zone = TimeZone.create( "Test", 43200 )
-    assert_equal Date.new(2004,7,26), zone.today
-  end
-
-  def test_adjust_negative
-    zone = TimeZone.create( "Test", -4200 ) # 4200s == 70 mins
-    assert_equal Time.utc(2004,7,24,23,55,0), zone.adjust(Time.utc(2004,7,25,1,5,0))
+    zone = TimeZone['Eastern Time (US & Canada)']
+    assert_equal "-05:00", zone.formatted_offset
+    assert_equal "-0500", zone.formatted_offset(false)
   end
-
-  def test_adjust_positive
-    zone = TimeZone.create( "Test", 4200 )
-    assert_equal Time.utc(2004,7,26,1,5,0), zone.adjust(Time.utc(2004,7,25,23,55,0))
-  end
-
-  def test_unadjust
-    zone = TimeZone.create( "Test", 4200 )
-    expect = Time.utc(2004,7,24,23,55,0).to_a[0,6]
-    actual = zone.unadjust(Time.utc(2004,7,25,1,5,0)).to_a[0,6]
-    assert_equal expect, actual
-  end
-
+  
   def test_zone_compare
-    zone1 = TimeZone.create( "Test1", 4200 )
-    zone2 = TimeZone.create( "Test1", 5600 )
-    assert zone1 < zone2
-    assert zone2 > zone1
-
-    zone1 = TimeZone.create( "Able", 10000 )
-    zone2 = TimeZone.create( "Zone", 10000 )
+    zone1 = TimeZone['Central Time (US & Canada)'] # offset -0600
+    zone2 = TimeZone['Eastern Time (US & Canada)'] # offset -0500
     assert zone1 < zone2
     assert zone2 > zone1
-
-    zone1 = TimeZone.create( "Able", 10000 )
     assert zone1 == zone1
   end
-
+  
   def test_to_s
-    zone = TimeZone.create( "Test", 4200 )
-    assert_equal "(UTC+01:10) Test", zone.to_s
+    assert_equal "(GMT+03:00) Moscow", TimeZone['Moscow'].to_s
   end
-
+  
   def test_all_sorted
     all = TimeZone.all
     1.upto( all.length-1 ) do |i|
       assert all[i-1] < all[i]
     end
   end
-
+  
   def test_index
     assert_nil TimeZone["bogus"]
-    assert_not_nil TimeZone["Central Time (US & Canada)"]
-    assert_not_nil TimeZone[8]
+    assert_instance_of TimeZone, TimeZone["Central Time (US & Canada)"]
+    assert_instance_of TimeZone, TimeZone[8]
     assert_raises(ArgumentError) { TimeZone[false] }
   end
   
   def test_new
-    a = TimeZone.new("Berlin")
-    b = TimeZone.new("Berlin")
-    assert_same a, b
-    assert_nil TimeZone.new("bogus")
+    assert_equal TimeZone["Central Time (US & Canada)"], TimeZone.new("Central Time (US & Canada)")
   end
   
   def test_us_zones
@@ -96,3 +112,4 @@ class TimeZoneTest < Test::Unit::TestCase
     assert !TimeZone.us_zones.include?(TimeZone["Kuala Lumpur"])
   end 
 end
+