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//! A macro for running `async fn` tests. //! //! Runs tests with [`safina::block_on`](https://docs.rs/safina/latest/safina/fn.block_on.html). //! //! Related crates: //! - [`safina`](https://crates.io/crates/safina) - safe async runtime //! - [`safina-timer`](https://crates.io/crates/safina-timer) - safe async sleep functions //! - [`safina-async-test`](https://crates.io/crates/safina-async-test) - macro for running async tests //! //! # Limitations //! - Requires Rust `nightly` because safina does //! //! # Examples //! ```rust //! # use safina_async_test::async_test; //! # async fn an_async_fn() -> Result<(), std::io::Error> { Ok(()) } //! #[async_test] //! async fn test1() { //! an_async_fn().await.unwrap(); //! } //! ``` //! //! ```rust //! # use safina_async_test::async_test; //! # use std::boxed::Box; //! # async fn background_task() {} //! # async fn do_request() -> Result<u8, std::io::Error> { Ok(42) } //! #[async_test] //! async fn test2() { //! safina::increase_threads_to(1); //! safina::spawn(Box::pin(background_task())); //! assert_eq!(42, do_request().await.unwrap()); //! } //! ``` //! //! # Documentation //! https://docs.rs/safina-async-test //! //! # Alternatives //! - [`async_std::test`](https://docs.rs/async-std/latest/async_std/attr.test.html) //! - [`futures_await_test::async_test`](https://docs.rs/futures-await-test/0.3.0/futures_await_test/) //! - [`tokio::test`](https://docs.rs/tokio/latest/tokio/attr.test.html) //! //! # Release Process //! 1. Edit `Cargo.toml` and bump version number. //! 1. Run `./release.sh` //! //! # Changelog //! - v0.1.1 - First published version //! //! # TO DO //! - DONE - Implement as declarative macro. UX is bad. //! - DONE - Implement as procedural macro. //! - DONE - Report errors nicely //! - DONE - Drop finished futures //! - Publish on crates.io #![forbid(unsafe_code)] use proc_macro; use proc_macro2::{Ident, TokenStream, TokenTree}; use quote::quote_spanned; #[proc_macro_attribute] pub fn async_test( attr: proc_macro::TokenStream, item: proc_macro::TokenStream, ) -> proc_macro::TokenStream { let mut result = proc_macro::TokenStream::from(impl_async_test( proc_macro2::TokenStream::from(attr.clone()), proc_macro2::TokenStream::from(item.clone()), )); result.extend(item); // let mut token_stream_string = String::new(); // for tree in result { // token_stream_string.push_str(format!("tree: {:?}\n", tree).as_str()); // } // panic!("TokenStream:\n{}", token_stream_string); result } fn impl_async_test(attr: TokenStream, item: TokenStream) -> TokenStream { for tree in attr { return quote_spanned!(tree.span()=>compile_error!("parameters not allowed");); } // Ident { ident: "async", span: #0 bytes(50..55) } // Ident { ident: "fn", span: #0 bytes(56..58) } // Ident { ident: "should_run_async_fn", span: #0 bytes(59..78) } // Group { delimiter: Parenthesis, stream: TokenStream [], span: ... // Group { delimiter: Brace, stream: TokenStream [Ident { ident: "println",... let mut iter = item.into_iter(); let first = iter.next(); if let ( Some(TokenTree::Ident(ref ident_async)), Some(TokenTree::Ident(ref ident_fn)), Some(TokenTree::Ident(ref ident_name)), ) = (&first, iter.next(), iter.next()) { if ident_async.to_string() == "async" && ident_fn.to_string() == "fn" { let async_name = ident_name.to_string() + "_"; let ident_async_name = Ident::new(&async_name, ident_name.span()); return quote_spanned!(ident_name.span()=> #[test] pub fn #ident_async_name () { safina::block_on(std::boxed::Box::pin( #ident_name ())) } ); } } if let Some(tree) = first { return quote_spanned!(tree.span()=>compile_error!("expected async fn");); } else { panic!("expected async fn"); } } // The version below has two drawbacks: // 1. IDEs don't know that the stuff inside `async_test! { async fn test1() { ... } }` is a // function, so they don't provide formatting, auto-complete, or other useful editor functions. // This is a fatal flaw. // 2. It puts the test in a module with the same name as the test function, // and a test function named `async_test`. // So for `async_test! { async fn test1() {...} }` below, it makes // `mod test1 { #[test] fn async_test() {...} }`. // This makes IDE test output more verbose. Each test appears as its own category. // // macro_rules! async_test { // (async fn $name:ident () $body:block) => { // async fn $name() $body // // mod $name { // #[test] // fn async_test () { // safina::block_on(std::boxed::Box::pin(super::$name())) // } // } // } // } // // async_test! { // async fn test1() { // println!("test1"); // } // } // The version below requires the user to keep the two names in sync. // Also, the error messages are not great. // // macro_rules! async_test { // ($name:ident) => { // mod $name { // #[test] // fn async_test () { // safina::block_on(std::boxed::Box::pin(super::$name())) // } // } // } // } // // async_test!(test1); // async fn test1() { // println!("test1"); // } // // async_test!(test1); // error[E0428]: the name `test1` is defined multiple times // async fn test2() { // println!("test2"); // } // // async_test!(test3); // error[E0423]: expected function, found module `super::test3` // async fn test4() { // println!("test4"); // }