diff --git a/Gemfile b/Gemfile
index d8b5a7a..a08dcbd 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,10 +1,9 @@
 source "https://rubygems.org"
 
-# Specify your gem's dependencies in time.gemspec
 gemspec
 
 group :development do
   gem "rake", "~> 13.2"
   gem "test-unit"
-  gem "test-unit-ruby-core"
+  gem "test-unit-ruby-core", ">= 1.0.7"
 end
diff --git a/test/test_time.rb b/test/test_time.rb
index 06db77b..55964d0 100644
--- a/test/test_time.rb
+++ b/test/test_time.rb
@@ -74,9 +74,6 @@ def test_rfc2822_nonlinear
   if defined?(Ractor)
     def test_rfc2822_ractor
       assert_ractor(<<~RUBY, require: 'time')
-        class Ractor
-          alias value take unless method_defined? :value # compat with Ruby 3.4 and olders
-        end
         actual = Ractor.new { Time.rfc2822("Fri, 21 Nov 1997 09:55:06 -0600") }.value
         assert_equal(Time.utc(1997, 11, 21, 9, 55, 6) + 6 * 3600, actual)
       RUBY