Follow-up from "Do not outdate merge train cars if skip-train setting is enabled"
The following discussion from !132325 should be addressed:
- [ ] @group_9970_bot_58e69a7d2ace73c7373ac2bc2a5cabd0 started a [discussion](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/132325#note_1581300341): (+1 comment)
>
> ```suggestion
> let_it_be(:project) { create(:project, :public, :repository, creator: user, namespace: user.namespace) }
> ```
>
> Project creations are very slow. To improve test performance, consider using `let_it_be`, `build`, or `build_stubbed` instead.
>
> ⚠️ **Warning**: If your test modifies data, `let_it_be` may be unsuitable, and cause state leaks! Use `let_it_be_with_reload` or `let_it_be_with_refind` instead.
>
> Unsure which method to use? See the [testing best practices](https://docs.gitlab.com/ee/development/testing_guide/best_practices.html#optimize-factory-usage)
> for background information and alternative options for optimizing factory usage.
>
> If you're concerned about causing state leaks, or if you know `let` or `let!` are the better options, ignore this comment.
>
> ([Improve this message?](https://gitlab.com/gitlab-org/gitlab/-/blob/master/tooling/danger/specs/project_factory_suggestion.rb))
>
>
> <!-- "generated_by_2677df" -->
> @drew:
> Please see the most recent commit in this MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/132325/diffs?commit_id=04907840ea27057941dcf47404c1e15d6ee477be
>
> I've added a lot of extra setup here to avoid flakiness in these tests. There's a ton of shared state happening in this spec file that makes writing *multiple* tests that actually merge MRs very difficult.
>
> I'm opening a follow-up about this because it's a pain to work with, but certainly outside the scope of this MR.
issue