diff --git a/actionpack/test/dispatch/response_test.rb b/actionpack/test/dispatch/response_test.rb
index 67d6dea86f3928f38d89fab09b10057ef1a0a61f..a14083c6a26337d099dcf4d5dd4254ab42da2fc7 100644
--- a/actionpack/test/dispatch/response_test.rb
+++ b/actionpack/test/dispatch/response_test.rb
@@ -296,13 +296,8 @@ def test_only_set_charset_still_defaults_to_text_html
   end
 
   test "read content type with default charset utf-8" do
-    original = ActionDispatch::Response.default_charset
-    begin
-      resp = ActionDispatch::Response.new(200, "Content-Type" => "text/xml")
-      assert_equal("utf-8", resp.charset)
-    ensure
-      ActionDispatch::Response.default_charset = original
-    end
+    resp = ActionDispatch::Response.new(200, "Content-Type" => "text/xml")
+    assert_equal("utf-8", resp.charset)
   end
 
   test "read content type with charset utf-16" do