Fixes OpenStruct use in design_management specs

Fixes OpenStruct use as Ruby 3 discourages it

Changelog: other

.rubocop_todo/style/open_struct_use.yml

@@ -30,8 +30,6 @@ Style/OpenStructUse:
   - spec/lib/gitlab/gitaly_client/diff_stitcher_spec.rb
   - spec/lib/gitlab/legacy_github_import/project_creator_spec.rb
   - spec/lib/gitlab/quick_actions/command_definition_spec.rb
-  - spec/models/design_management/design_action_spec.rb
-  - spec/models/design_management/design_at_version_spec.rb
   - spec/services/projects/import_service_spec.rb
   - spec/services/system_note_service_spec.rb
   - spec/support/helpers/import_spec_helper.rb

spec/models/design_management/design_action_spec.rb

@@ -46,7 +46,7 @@ RSpec.describe DesignManagement::DesignAction do
 
   describe '#gitaly_action' do
     let(:path) { 'some/path/somewhere' }
-    let(:design) { OpenStruct.new(full_path: path) }
+    let(:design) { double('path', full_path: path) }
 
     subject { described_class.new(design, action, content) }
 
@@ -75,7 +75,7 @@ RSpec.describe DesignManagement::DesignAction do
 
   describe '#issue_id' do
     let(:issue_id) { :foo }
-    let(:design) { OpenStruct.new(issue_id: issue_id) }
+    let(:design) { double('id', issue_id: issue_id) }
 
     subject { described_class.new(design, :delete) }
 

spec/models/design_management/design_at_version_spec.rb

@@ -59,7 +59,7 @@ RSpec.describe DesignManagement::DesignAtVersion do
     it 'rejects objects with the same id and the wrong class' do
       dav = build_stubbed(:design_at_version)
 
-      expect(dav).not_to eq(OpenStruct.new(id: dav.id))
+      expect(dav).not_to eq(double('id', id: dav.id))
     end
 
     it 'expects objects to be of the same type, not subtypes' do