1 files changed, 4 insertions, 1 deletions
diff --git a/activesupport/test/multibyte_test_helpers.rb b/activesupport/test/multibyte_test_helpers.rb
index 597f949059..8839b75601 100644
--- a/activesupport/test/multibyte_test_helpers.rb
+++ b/activesupport/test/multibyte_test_helpers.rb
@@ -4,6 +4,9 @@ module MultibyteTestHelpers
   UNICODE_STRING = 'こにちわ'
   ASCII_STRING = 'ohayo'
   BYTE_STRING = "\270\236\010\210\245"
+  if BYTE_STRING.respond_to?(:force_encoding)
+    BYTE_STRING.force_encoding("ASCII-8BIT")
+  end
 
   def chars(str)
     ActiveSupport::Multibyte::Chars.new(str)
@@ -16,4 +19,4 @@ module MultibyteTestHelpers
   def assert_equal_codepoints(expected, actual, message=nil)
     assert_equal(inspect_codepoints(expected), inspect_codepoints(actual), message)
   end
-end
-\ No newline at end of file
+end