4 files changed, 96 insertions, 0 deletions
diff --git a/spec/ruby/core/warning/categories_spec.rb b/spec/ruby/core/warning/categories_spec.rb
new file mode 100644
index 0000000000..1e310ef38b
--- /dev/null
+++ b/spec/ruby/core/warning/categories_spec.rb
@@ -0,0 +1,12 @@
+require_relative '../../spec_helper'
+
+ruby_version_is "3.4" do
+  describe "Warning.categories" do
+    # There might be more, but these are standard across Ruby implementations
+    it "returns the list of possible warning categories" do
+      Warning.categories.should.include? :deprecated
+      Warning.categories.should.include? :experimental
+      Warning.categories.should.include? :performance
+    end
+  end
+end
diff --git a/spec/ruby/core/warning/element_reference_spec.rb b/spec/ruby/core/warning/element_reference_spec.rb
index 8cb4018c20..c0ed37ef13 100644
--- a/spec/ruby/core/warning/element_reference_spec.rb
+++ b/spec/ruby/core/warning/element_reference_spec.rb
@@ -2,6 +2,10 @@ require_relative '../../spec_helper'
 
 describe "Warning.[]" do
   it "returns default values for categories :deprecated and :experimental" do
+    # If any warning options were set on the Ruby that will be executed, then
+    # it's possible this test will fail. In this case we will skip this test.
+    skip if ruby_exe.any? { |opt| opt.start_with?("-W") }
+
     ruby_exe('p [Warning[:deprecated], Warning[:experimental]]').chomp.should == "[false, true]"
     ruby_exe('p [Warning[:deprecated], Warning[:experimental]]', options: "-w").chomp.should == "[true, true]"
   end
diff --git a/spec/ruby/core/warning/performance_warning_spec.rb b/spec/ruby/core/warning/performance_warning_spec.rb
new file mode 100644
index 0000000000..ab0badcd3d
--- /dev/null
+++ b/spec/ruby/core/warning/performance_warning_spec.rb
@@ -0,0 +1,28 @@
+require_relative '../../spec_helper'
+
+
+describe "Performance warnings" do
+  guard -> { ruby_version_is("3.4") || RUBY_ENGINE == "truffleruby" } do
+    # Optimising Integer, Float or Symbol methods is kind of implementation detail
+    # but multiple implementations do so. So it seems reasonable to have a test case
+    # for at least one such common method.
+    # See https://bugs.ruby-lang.org/issues/20429
+    context "when redefined optimised methods" do
+      it "emits performance warning for redefining Integer#+" do
+        code = <<~CODE
+          Warning[:performance] = true
+
+          class Integer
+            ORIG_METHOD = instance_method(:+)
+
+            def +(...)
+              ORIG_METHOD.bind(self).call(...)
+            end
+          end
+        CODE
+
+        ruby_exe(code, args: "2>&1").should.include?("warning: Redefining 'Integer#+' disables interpreter and JIT optimizations")
+      end
+    end
+  end
+end
diff --git a/spec/ruby/core/warning/warn_spec.rb b/spec/ruby/core/warning/warn_spec.rb
index 8f96fe9287..2e4a822e02 100644
--- a/spec/ruby/core/warning/warn_spec.rb
+++ b/spec/ruby/core/warning/warn_spec.rb
@@ -97,6 +97,20 @@ describe "Warning.warn" do
     end
   end
 
+  ruby_version_is "3.4" do
+    it "warns when category is :strict_unused_block but Warning[:strict_unused_block] is false" do
+      warn_strict_unused_block = Warning[:strict_unused_block]
+      Warning[:strict_unused_block] = true
+      begin
+        -> {
+          Warning.warn("foo", category: :strict_unused_block)
+        }.should complain("foo")
+      ensure
+        Warning[:strict_unused_block] = warn_strict_unused_block
+      end
+    end
+  end
+
   it "doesn't print message when category is :deprecated but Warning[:deprecated] is false" do
     warn_deprecated = Warning[:deprecated]
     Warning[:deprecated] = false
@@ -121,6 +135,44 @@ describe "Warning.warn" do
     end
   end
 
+  ruby_version_is "3.4" do
+    it "doesn't print message when category is :strict_unused_block but Warning[:strict_unused_block] is false" do
+      warn_strict_unused_block = Warning[:strict_unused_block]
+      Warning[:strict_unused_block] = false
+      begin
+        -> {
+          Warning.warn("foo", category: :strict_unused_block)
+        }.should_not complain
+      ensure
+        Warning[:strict_unused_block] = warn_strict_unused_block
+      end
+    end
+  end
+
+  ruby_bug '#20573', ''...'3.4' do
+    it "isn't called by Kernel.warn when category is :deprecated but Warning[:deprecated] is false" do
+      warn_deprecated = Warning[:deprecated]
+      begin
+        Warning[:deprecated] = false
+        Warning.should_not_receive(:warn)
+        Kernel.warn("foo", category: :deprecated)
+      ensure
+        Warning[:deprecated] = warn_deprecated
+      end
+    end
+
+    it "isn't called by Kernel.warn when category is :experimental but Warning[:experimental] is false" do
+      warn_experimental = Warning[:experimental]
+      begin
+        Warning[:experimental] = false
+        Warning.should_not_receive(:warn)
+        Kernel.warn("foo", category: :experimental)
+      ensure
+        Warning[:experimental] = warn_experimental
+      end
+    end
+  end
+
   it "prints the message when VERBOSE is false" do
     -> { Warning.warn("foo") }.should complain("foo")
   end