macros: Disambiguate the built-in #[test] attribute in macro expansion.

[jebrosen]

tokio::test and related macros now use the absolute path ::core::prelude::v1::test to refer to the built-in test macro.

This absolute path was introduced in rust-lang/rust#62086.

Motivation

The following example currently fails due to shadowing of the test macro (playground):

use tokio::test;

#[test]
async fn mytest() { }

 Compiling playground v0.0.1 (/playground)
error: the async keyword is missing from the function declaration
 --> src/lib.rs:4:7
  |
4 | async fn mytest() { }
  |       ^^

error: the async keyword is missing from the function declaration
 --> src/lib.rs:4:7
  |
4 | async fn mytest() { }
  |       ^^

[LucioFranco]

I assume this is not a breaking change?

[jebrosen]

I assume this is not a breaking change?

I guess that depends on whether or not this is supposed to be supported today:

use some_other_lib::test;

#[tokio::test]
async fn some_test() { }

Currently, the #[some_other_lib::test] attribute would be used instead of #[test] from core - this PR would break that, by always using #[test] from core.

[LucioFranco]

seems fine to me

[Darksonn]

CI appears to be stuck, and I can't restart it.

[jebrosen]

The CI failures (on Windows) appear to be unrelated to this change:

test threaded_scheduler_1_thread::runtime_in_thread_local ... test threaded_scheduler_1_thread::runtime_in_thread_local has been running for over 60 seconds
test threaded_scheduler_1_thread::shutdown_timeout ... test threaded_scheduler_1_thread::shutdown_timeout has been running for over 60 seconds

They look familiar, but I don't know off the top of my head which other PR did this.

[IThawk]

I want to know how to test async function.

[Darksonn]

Please open a new discussion if you have a question.