diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 6c47383..7f4e42f 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -11,15 +11,8 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby: [ "2.7", "3.0", "3.1", "3.2", jruby ]
-        active_support: [ "6.0", "7.0" ]
-        exclude:
-          - ruby: "3.0"
-            active_support: "6.0"
-          - ruby: "3.1"
-            active_support: "6.0"
-          - ruby: "3.2"
-            active_support: "6.0"
+        ruby: [ "3.2", "3.3", "3.4", "4.0" ]
+        active_support: [ "8.0", "8.1" ]
     name: Ruby ${{ matrix.ruby }} - ActiveSupport ${{ matrix.active_support }}
     env:
       ACTIVE_SUPPORT_VERSION: ${{ matrix.active_support }}
diff --git a/clockwork.gemspec b/clockwork.gemspec
index 9f5c420..3b46b7f 100644
--- a/clockwork.gemspec
+++ b/clockwork.gemspec
@@ -19,6 +19,9 @@ Gem::Specification.new do |s|
 
   s.add_dependency(%q<tzinfo>)
   s.add_dependency(%q<activesupport>)
+  s.add_dependency(%q<base64>)
+  s.add_dependency(%q<bigdecimal>)
+  s.add_dependency(%q<ostruct>)
 
   s.add_development_dependency "rake"
   s.add_development_dependency "daemons"
diff --git a/test/manager_test.rb b/test/manager_test.rb
index 2bb5d79..c63040a 100644
--- a/test/manager_test.rb
+++ b/test/manager_test.rb
@@ -3,6 +3,7 @@
 require 'mocha/minitest'
 require 'time'
 require 'active_support/time'
+require 'stringio'
 
 describe Clockwork::Manager do
   before do
@@ -117,7 +118,7 @@ def assert_wont_run(t)
     @manager.handler { raise 'boom' }
     @manager.every(1.minute, 'myjob')
 
-    mocked_logger = MiniTest::Mock.new
+    mocked_logger = Minitest::Mock.new
     mocked_logger.expect :error, true, [RuntimeError]
     @manager.configure { |c| c[:logger] = mocked_logger }
     @manager.tick(Time.now)
diff --git a/test/samples/signal_test.rb b/test/samples/signal_test.rb
index 98def4d..1a420a0 100644
--- a/test/samples/signal_test.rb
+++ b/test/samples/signal_test.rb
@@ -1,5 +1,6 @@
 require 'clockwork'
 require 'active_support/time'
+require 'stringio'
 
 module Clockwork
   LOGFILE = File.expand_path('../../tmp/signal_test.log', __FILE__)