diff --git a/Gemfile b/Gemfile
index f1bf6b395..a605ac476 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,7 +6,6 @@ gemspec
 # Development dependencies
 gem "rake"
 gem "test-unit"
-gem "test-unit-rr"
 gem "rspec"
 gem "racc"
 gem "rubocop"
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 55bc999fe..bfbc15905 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -4,7 +4,6 @@
 require "stringio"
 require "open3"
 require "test/unit"
-require "test/unit/rr"
 
 begin
   require "amber"
@@ -41,16 +40,19 @@ def type_name(string)
     end
   end
 
-  def silence_errors
-    stub(RBS.logger).error do
-      yield
-    end
-  end
-
   def silence_warnings
-    stub(RBS.logger).warn do
-      yield
+    klass = RBS.logger.class
+    original_method = klass.instance_method(:warn)
+
+    klass.remove_method(:warn)
+    klass.define_method(:warn) do |*args, &block|
+      block&.call()
     end
+
+    yield
+  ensure
+    klass.remove_method(:warn)
+    klass.define_method(:warn, original_method)
   end
 
   class SignatureManager