Deprecate top_level_group? and test it in a Cop class

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Changelog
 
 ## Master (Unreleased)
+- Deprecate `top_level_group?` private method on TopLevelGroup mixin. ([@corsonknowles])
 
 ## 3.1.0 (2024-10-01)
 

lib/rubocop/cop/rspec/mixin/top_level_group.rb

@@ -7,6 +7,11 @@ module RSpec
       module TopLevelGroup
         extend RuboCop::NodePattern::Macros
 
+        DEPRECATED_METHOD_WARNING =
+          'top_level_group? is deprecated and will be ' \
+          'removed in the next major version of Rubocop/RSpec.' \
+          'Please copy the method if you need it for you mixin.'
+
         def on_new_investigation
           super
 
@@ -29,6 +34,7 @@ def on_top_level_example_group(_node); end
         def on_top_level_group(_node); end
 
         def top_level_group?(node)
+          warn DEPRECATED_METHOD_WARNING
           top_level_groups.include?(node)
         end
 

spec/rubocop/cop/rspec/describe_class_spec.rb

@@ -215,4 +215,23 @@
       RUBY
     end
   end
+
+  context 'with mixin tests' do
+    describe '#top_level_group?' do
+      subject(:cop_with_top_level_group_mixin) do
+        described_class.new
+      end
+
+      it 'warns because it is deprecated' do
+        # rubocop:disable RSpec/SubjectStub
+        allow(cop_with_top_level_group_mixin).to receive(:warn)
+        allow(cop_with_top_level_group_mixin).to receive(:top_level_groups)
+          .and_return([])
+
+        cop_with_top_level_group_mixin.send(:top_level_group?, nil)
+        expect(cop_with_top_level_group_mixin).to have_received(:warn)
+        # rubocop:enable RSpec/SubjectStub
+      end
+    end
+  end
 end