New testing style isn't documented

[epage]

Problem

With cargo-add and #10581, we are getting a new way of testing but its not in the contributing guide

Steps

See docs

Possible Solution(s)

Docs should cover

• writing new tests
  • multiple bin calls to verify in a test
  • cover .keep files
  • cover curr_dir
• updating tests

Notes

Blocked on #10626 and #10627 as they will change things up

Version

_No response_cover

[weihanglo]

We have docs here https://doc.crates.io/contrib/tests/writing.html#ui-tests. I believe this can be closed now. If we have more ideas to enhance, we could reopen or file a new one.