Add specs for Module#undefined_instance_methods

core/module/undefined_instance_methods_spec.rb

@@ -0,0 +1,26 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+describe "Module#undefined_instance_methods" do
+  ruby_version_is "3.2" do
+    it "returns methods undefined in the class" do
+      methods = ModuleSpecs::Parent.undefined_instance_methods
+      methods.should == [:undefed_method]
+    end
+
+    it "returns inherited methods undefined in the class" do
+      methods = ModuleSpecs::Child.undefined_instance_methods
+      methods.should include(:parent_method, :another_parent_method)
+    end
+
+    it "returns methods from an included module that are undefined in the class" do
+      methods = ModuleSpecs::Grandchild.undefined_instance_methods
+      methods.should include(:super_included_method)
+    end
+
+    it "does not returns ancestors undefined methods" do
+      methods = ModuleSpecs::Grandchild.undefined_instance_methods
+      methods.should_not include(:parent_method, :another_parent_method)
+    end
+  end
+end