By moving `block_on` to an auxiliary crate, we avoid having to keep a separate
copy of it in every async test.
(This also incorporates some small tweaks to the headers in `await_ready.rs`.)
Currently `await` is only counted towards coverage if the containing
function is suspended and resumed at least once. This is because it
expands to code which contains a branch on the discriminant of `Poll`.
By treating it like a branching macro (e.g. `assert!`), these
implementation details will be hidden from the coverage results.
coverage: Format all coverage tests with `rustfmt`
As suggested by <https://github.com/rust-lang/rust/pull/119984#discussion_r1452856806>.
Test files in `tests/` are normally ignored by `x fmt`, but sometimes those files end up being run through `rustfmt` anyway, either by `rust-analyzer` or by hand.
When that happens, it's annoying to have to manually revert formatting changes that are unrelated to the actual changes being made. So it's helpful for the tests in the repository to already have standard formatting beforehand.
However, there are several coverage tests that deliberately use non-standard formatting, so that line counts reveal more information about where code regions begin and end. In those cases, we can use `#[rustfmt::skip]` to prevent that code from being disturbed.
``@rustbot`` label +A-code-coverage
These tests deliberately use non-standard formatting, so that the line
execution counts reported by `llvm-cov` reveal additional information about
where code regions begin and end.
