fix conditions when DateTime#to_date and DateTime#xmlschema methods are defined

activesupport/lib/active_support/core_ext/date_time/conversions.rb

@@ -60,7 +60,7 @@ class DateTime
   # Converts self to a Ruby Date object; time portion is discarded
   def to_date
     ::Date.new(year, month, day)
-  end unless method_defined?(:to_date)
+  end unless instance_methods(false).include?(:to_date)
 
   # Attempts to convert self to a Ruby Time object; returns self if out of range of Ruby Time class
   # If self has an offset other than 0, self will just be returned unaltered, since there's no clean way to map it to a Time
@@ -71,7 +71,7 @@ class DateTime
   # To be able to keep Times, Dates and DateTimes interchangeable on conversions
   def to_datetime
     self
-  end unless method_defined?(:to_datetime)
+  end unless instance_methods(false).include?(:to_datetime)
 
   def self.civil_from_format(utc_or_local, year, month=1, day=1, hour=0, min=0, sec=0)
     offset = utc_or_local.to_sym == :local ? local_offset : 0
@@ -81,7 +81,7 @@ class DateTime
   # Converts datetime to an appropriate format for use in XML
   def xmlschema
     strftime("%Y-%m-%dT%H:%M:%S%Z")
-  end unless method_defined?(:xmlschema)
+  end unless instance_methods(false).include?(:xmlschema)
   
   # Converts self to a floating-point number of seconds since the Unix epoch 
   def to_f

activesupport/test/abstract_unit.rb

@@ -18,7 +18,7 @@ ENV['NO_RELOAD'] = '1'
 require 'active_support'
 
 # Include shims until we get off 1.8.6
-require 'active_support/ruby/shim'
+require 'active_support/ruby/shim' if RUBY_VERSION < '1.8.7'
 
 def uses_memcached(test_name)
   require 'memcache'

activesupport/test/core_ext/date_time_ext_test.rb

@@ -26,11 +26,11 @@ class DateTimeExtCalculationsTest < Test::Unit::TestCase
   end
 
   def test_to_date
-    assert_equal Date.new(2005, 2, 21), DateTime.new(2005, 2, 21).to_date
+    assert_equal Date.new(2005, 2, 21), DateTime.new(2005, 2, 21, 14, 30, 0).to_date
   end
 
   def test_to_datetime
-    assert_equal DateTime.new(2005, 2, 21), DateTime.new(2005, 2, 21).to_datetime
+    assert_equal DateTime.new(2005, 2, 21, 14, 30, 0), DateTime.new(2005, 2, 21, 14, 30, 0).to_datetime
   end
 
   def test_to_time