3 files changed, 20 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/core_ext/string/encoding.rb b/activesupport/lib/active_support/core_ext/string/encoding.rb
new file mode 100644
index 0000000000..d4781bfe0c
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/string/encoding.rb
@@ -0,0 +1,11 @@
+class String
+  if defined?(Encoding) && "".respond_to?(:encode)
+    def encoding_aware?
+      true
+    end
+  else
+    def encoding_aware?
+      false
+    end
+  end
+end
+\ No newline at end of file
diff --git a/activesupport/lib/active_support/ruby/shim.rb b/activesupport/lib/active_support/ruby/shim.rb
index 4a9ac920e8..608b3fe4b9 100644
--- a/activesupport/lib/active_support/ruby/shim.rb
+++ b/activesupport/lib/active_support/ruby/shim.rb
@@ -15,6 +15,7 @@ require 'active_support/core_ext/enumerable'
 require 'active_support/core_ext/process/daemon'
 require 'active_support/core_ext/string/conversions'
 require 'active_support/core_ext/string/interpolation'
+require 'active_support/core_ext/string/encoding'
 require 'active_support/core_ext/rexml'
 require 'active_support/core_ext/time/conversions'
 require 'active_support/core_ext/file/path'
diff --git a/activesupport/test/core_ext/string_ext_test.rb b/activesupport/test/core_ext/string_ext_test.rb
index 97b08da0e4..09ce39bae2 100644
--- a/activesupport/test/core_ext/string_ext_test.rb
+++ b/activesupport/test/core_ext/string_ext_test.rb
@@ -439,6 +439,14 @@ class OutputSafetyTest < ActiveSupport::TestCase
   test 'emits normal string yaml' do
     assert_equal 'foo'.to_yaml, 'foo'.html_safe.to_yaml(:foo => 1)
   end
+
+  test 'knows whether it is encoding aware' do
+    if RUBY_VERSION >= "1.9"
+      assert 'ruby'.encoding_aware?
+    else
+      assert !'ruby'.encoding_aware?
+    end
+  end
 end
 
 class StringExcludeTest < ActiveSupport::TestCase