1 files changed, 33 insertions, 1 deletions
diff --git a/spec/ruby/core/kernel/warn_spec.rb b/spec/ruby/core/kernel/warn_spec.rb
index 79e78dd4a3..de08cd8cff 100644
--- a/spec/ruby/core/kernel/warn_spec.rb
+++ b/spec/ruby/core/kernel/warn_spec.rb
@@ -17,7 +17,7 @@ describe "Kernel#warn" do
     Kernel.should have_private_instance_method(:warn)
   end
 
-  it "requires multiple arguments" do
+  it "accepts multiple arguments" do
     Kernel.method(:warn).arity.should < 0
   end
 
@@ -114,6 +114,38 @@ describe "Kernel#warn" do
       end
     end
 
+    ruby_version_is "3.0" do
+      it "accepts :category keyword with a symbol" do
+        -> {
+          $VERBOSE = true
+          warn("message", category: :deprecated)
+        }.should output(nil, "message\n")
+      end
+
+      it "accepts :category keyword with nil" do
+        -> {
+          $VERBOSE = true
+          warn("message", category: nil)
+        }.should output(nil, "message\n")
+      end
+
+      it "accepts :category keyword with object convertible to symbol" do
+        o = Object.new
+        def o.to_sym; :deprecated; end
+        -> {
+          $VERBOSE = true
+          warn("message", category: o)
+        }.should output(nil, "message\n")
+      end
+
+      it "raises if :category keyword is not nil and not convertible to symbol" do
+        -> {
+          $VERBOSE = true
+          warn("message", category: Object.new)
+        }.should raise_error(TypeError)
+      end
+    end
+
     it "converts first arg using to_s" do
       w = KernelSpecs::WarnInNestedCall.new