Meets #15173:  Subprojects are not copied correctly and the hierarchy is lost

[``* `#15173` Subprojects are not copied correctly and the hierarchy is lost``](https://www.openproject.org/work_packages/15173)
You could also use an `around` block. I think this makes the intention a little clearer.

```ruby
around do |example|
   User.stub(:current).and_return(user) }
   example.run
   User.current = nil
   # why this rather than:
   # User.unstub(:current)
end
```