This test lasted about 7 years prior to it becoming flaky.
Today ... for whatever reason the test suite created 100 users
prior to running this spec. So the new user becomes user id 101
And... lo and behold:
```
1) PostSerializer a hidden post with add_raw enabled a hidden post shows the raw post only if authorized to see it
Failure/Error: expect(serialized_post_for_user(Fabricate(:user))[:raw]).to eq(nil)
expected: nil
got: "Raw contents of the post."
(compared using ==)
# ./spec/serializers/post_serializer_spec.rb:127:in `block (4 levels) in <main>'
```
716629dc0a