1 files changed, 51 insertions, 0 deletions
diff --git a/spec/ruby/core/module/method_defined_spec.rb b/spec/ruby/core/module/method_defined_spec.rb
index 62e0db8ee6..f5203917b4 100644
--- a/spec/ruby/core/module/method_defined_spec.rb
+++ b/spec/ruby/core/module/method_defined_spec.rb
@@ -46,4 +46,55 @@ describe "Module#method_defined?" do
 
     c.method_defined?(o).should == true
   end
+
+  ruby_version_is "2.6" do
+    # works as method_defined?(method_name)
+    describe "when passed true as a second optional argument" do
+      it "performs a lookup in ancestors" do
+        ModuleSpecs::Child.method_defined?(:public_child, true).should == true
+        ModuleSpecs::Child.method_defined?(:protected_child, true).should == true
+        ModuleSpecs::Child.method_defined?(:accessor_method, true).should == true
+        ModuleSpecs::Child.method_defined?(:private_child, true).should == false
+
+        # Defined in Parent
+        ModuleSpecs::Child.method_defined?(:public_parent, true).should == true
+        ModuleSpecs::Child.method_defined?(:protected_parent, true).should == true
+        ModuleSpecs::Child.method_defined?(:private_parent, true).should == false
+
+        # Defined in Module
+        ModuleSpecs::Child.method_defined?(:public_module, true).should == true
+        ModuleSpecs::Child.method_defined?(:protected_module, true).should == true
+        ModuleSpecs::Child.method_defined?(:private_module, true).should == false
+
+        # Defined in SuperModule
+        ModuleSpecs::Child.method_defined?(:public_super_module, true).should == true
+        ModuleSpecs::Child.method_defined?(:protected_super_module, true).should == true
+        ModuleSpecs::Child.method_defined?(:private_super_module, true).should == false
+      end
+    end
+
+    describe "when passed false as a second optional argument" do
+      it "checks only the class itself" do
+        ModuleSpecs::Child.method_defined?(:public_child, false).should == true
+        ModuleSpecs::Child.method_defined?(:protected_child, false).should == true
+        ModuleSpecs::Child.method_defined?(:accessor_method, false).should == true
+        ModuleSpecs::Child.method_defined?(:private_child, false).should == false
+
+        # Defined in Parent
+        ModuleSpecs::Child.method_defined?(:public_parent, false).should == false
+        ModuleSpecs::Child.method_defined?(:protected_parent, false).should == false
+        ModuleSpecs::Child.method_defined?(:private_parent, false).should == false
+
+        # Defined in Module
+        ModuleSpecs::Child.method_defined?(:public_module, false).should == false
+        ModuleSpecs::Child.method_defined?(:protected_module, false).should == false
+        ModuleSpecs::Child.method_defined?(:private_module, false).should == false
+
+        # Defined in SuperModule
+        ModuleSpecs::Child.method_defined?(:public_super_module, false).should == false
+        ModuleSpecs::Child.method_defined?(:protected_super_module, false).should == false
+        ModuleSpecs::Child.method_defined?(:private_super_module, false).should == false
+      end
+    end
+  end
 end