Include `can_leave` for a group

app/serializers/group_child_entity.rb

@@ -43,7 +43,7 @@ class GroupChildEntity < Grape::Entity
 
   # Group only attributes
   expose :children_count, :leave_path, :parent_id, :number_projects_with_delimiter,
-         :number_users_with_delimiter, :project_count, :subgroup_count,
+         :number_users_with_delimiter, :project_count, :subgroup_count, :can_leave,
          unless: lambda { |_instance, _options| project? }
 
   def children_finder
@@ -66,6 +66,14 @@ class GroupChildEntity < Grape::Entity
     leave_group_group_members_path(object)
   end
 
+  def can_leave
+    if membership = object.members_and_requesters.find_by(user: request.current_user)
+      can?(request.current_user, :destroy_group_member, membership)
+    else
+      false
+    end
+  end
+
   def number_projects_with_delimiter
     number_with_delimiter(project_count)
   end

spec/serializers/group_child_entity_spec.rb

@@ -83,6 +83,12 @@ describe GroupChildEntity do
       end
     end
 
+    it 'allows an owner to leave when there is another one' do
+      object.add_owner(create(:user))
+
+      expect(json[:can_leave]).to be_truthy
+    end
+
     it_behaves_like 'group child json'
   end
 end