prefering psych as the yaml parser if possible, fixing assertions for…

… YAML 1.1 compatibility

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

@@ -1,4 +1,10 @@
 require 'bigdecimal'
+
+begin
+  require 'psych'
+rescue LoadError
+end
+
 require 'yaml'
 
 class BigDecimal

activesupport/lib/active_support/time_with_zone.rb

@@ -137,7 +137,17 @@ def as_json(options = nil)
       end
     end
 
+    def encode_with(coder)
+      if coder.respond_to?(:represent_object)
+        coder.represent_object(nil, utc)
+      else
+        coder.represent_scalar(nil, utc.strftime("%Y-%m-%d %H:%M:%S.%9NZ"))
+      end
+    end
+
     def to_yaml(options = {})
+      return super if defined?(YAML::ENGINE) && !YAML::ENGINE.syck?
+
       utc.to_yaml(options)
     end
 

activesupport/test/core_ext/time_with_zone_test.rb

@@ -106,11 +106,11 @@ def test_xmlschema_with_fractional_seconds
   end
 
   def test_to_yaml
-    assert_equal "--- 2000-01-01 00:00:00 Z\n", @twz.to_yaml
+    assert_match(/^--- 2000-01-01 00:00:00(\.0+)?\s*Z\n/, @twz.to_yaml)
   end
 
   def test_ruby_to_yaml
-    assert_equal "--- \n:twz: 2000-01-01 00:00:00 Z\n", {:twz => @twz}.to_yaml
+    assert_match(/---\s*\n:twz: 2000-01-01 00:00:00(\.0+)?\s*Z\n/, {:twz => @twz}.to_yaml)
   end
 
   def test_httpdate