diff --git a/test/testaddress.rb b/test/testaddress.rb
index 5a4e22f..76dc54f 100644
--- a/test/testaddress.rb
+++ b/test/testaddress.rb
@@ -809,14 +809,14 @@ def test_bug_23043
   def test_invalid_addresses()
     # The display name isn't encoded -- bad, but we parse it.
     validate_case\
-    ["\322\315\322 \312\353\363\341 <bar@foo.invalid>",
-      [ { :name => "\322\315\322 \312\353\363\341",
-	  :display_name => "\322\315\322 \312\353\363\341",
+    ["\322\315\322 \312\353\363\341 <bar@foo.invalid>".force_encoding('ASCII-8BIT'),
+      [ { :name => "\322\315\322 \312\353\363\341".force_encoding('ASCII-8BIT'),
+	  :display_name => "\322\315\322 \312\353\363\341".force_encoding('ASCII-8BIT'),
 	  :address => 'bar@foo.invalid',
 	  :comments => nil,
 	  :domain => 'foo.invalid',
 	  :local => 'bar',
-	  :format => "\"\322\315\322 \312\353\363\341\" <bar@foo.invalid>",
+	  :format => "\"\322\315\322 \312\353\363\341\" <bar@foo.invalid>".force_encoding('ASCII-8BIT'),
 	} ] ]
   end
 
diff --git a/test/testbase.rb b/test/testbase.rb
index 0dfb8af..8d9995d 100644
--- a/test/testbase.rb
+++ b/test/testbase.rb
@@ -39,7 +39,7 @@
 end
 
 class TestBase < Test::Unit::TestCase
-  include Config
+  include RbConfig
 
   attr_reader :scratch_dir
 
diff --git a/test/testmessage.rb b/test/testmessage.rb
index 9ba7347..2ed6cc2 100644
--- a/test/testmessage.rb
+++ b/test/testmessage.rb
@@ -141,7 +141,7 @@ def test_add_part
   def test_decode
     message = RMail::Message.new
 
-    all_bytes = ''
+    all_bytes = ''.force_encoding('ASCII-8BIT')
     0.upto(255) do |i|
       all_bytes << i
     end