Consider supporting wasm-bindgen-test for async test

[FirelightFlagboy]

Currently I've the following sample test that I would like to make it work using rstest and wasm_bindgen_test to be able to run in using wasm-pack test.

use wasm_bindgen_test::wasm_bindgen_test
use rstest::rstest;
use gloo_timers::future::sleep;
use std::time::Duration;

#[rstest]
#[case(200)]
#[case(100)]
#[wasm_bingen_test]
async fn test_sleep(#[case] duration: u32) {
    sleep(Duration::from_millis(duration).await
}

The problem

The test could not compile because it try to use async_std in this context which would not work with wasm-pack.

error[E0433]: failed to resolve: use of undeclared crate or module `async_std`
 --> [redacted]/tests/foo.rs:7:1
  |
7 | #[rstest]
  | ^^^^^^^^^ use of undeclared crate or module `async_std`
  |
  = note: this error originates in the attribute macro `rstest` (in Nightly builds, run with -Z macro-backtrace for more info)
For more information about this error, try `rustc --explain E0433`.

Additional information

I've added the macro expansion using cargo-expand below (we can see the use of async_std):

cargo expand --test foo --target wasm32-unknown-unknown

#![feature(prelude_import)]
#![cfg(target_arch = "wasm32")]
#[prelude_import]
use std::prelude::rust_2021::*;
#[macro_use]
extern crate std;
use gloo_timers::future::sleep;
use rstest::rstest;
use std::time::Duration;
use wasm_bindgen_test::wasm_bindgen_test;

#[cfg(test)]
async fn test_sleep(duration: u32) {
    {
        sleep(Duration::from_millis(duration)).await;
    }
}

#[cfg(test)]
mod test_sleep {
    use super::*;
    #[no_mangle]
    pub extern "C" fn __wbgt_case_1_0(cx: &::wasm_bindgen_test::__rt::Context) {
        let test_name = "foo::test_sleep::case_1";
        cx.execute_async(test_name, case_1, None);
    }
    #[async_std::test]
    async fn case_1() {
        let duration = 200;
        test_sleep(duration).await
    }
    #[no_mangle]
    pub extern "C" fn __wbgt_case_2_1(cx: &::wasm_bindgen_test::__rt::Context) {
        let test_name = "foo::test_sleep::case_2";
        cx.execute_async(test_name, case_2, None);
    }
    #[async_std::test]
    async fn case_2() {
        let duration = 100;
        test_sleep(duration).await
    }
}
#[rustc_main]
#[no_coverage]
pub fn main() -> () {
    extern crate test;
    test::test_main_static(&[])
}

[la10736]

You're right. I'm working on wasm in the last moths and I meet this issue too.

Maybe I'll introduce this fix in the next release....

BTW I'm using the following workaround that I hope could work for you too

At crate level

#[cfg(test)]
pub(crate) mod wasm {
    use wasm_bindgen_test::wasm_bindgen_test as test;
}

Where you're writeing your tests

tests {
    use crate::wasm;
        
    #[rstest]
    #[wasm::test]
    async fn grpc_process(_init: ()) {
        ....
    }
}

[la10736]

I forgot to mention the cause.... rstest accept only attribute where the last segment is test as test injected attribute.

[FirelightFlagboy]

Yes that's stated in inject test attribute

Just the attributes that ends with test (last path segment) can be injected: in this case the #[actix_rt::test] attribute will replace the standard #[test] attribute.