Provide mechanism to disable test execution

[davidbarsky]

Hi! I'm using Trybuild to test some procedural macros in the AWS Lambda Runtime for Rust, and I'm really liking it!

I do have a question, though: there any way to disable TestCases::pass from running the code under test/providing a mechanism to only check for compiler errors?

At runtime, the macro I'm testing with Trybuild makes several assumptions about its environment that include a running server + several environment variables. This results in tests failing with a server connection error, rather than passing due to correct usage of the macro. More concretely, it'd be really handy for my use case if run_test would pass check rather than run to Cargo.

Thanks again for this crate! It's really nice to use, and the test reports are beautifully rendered.

[dtolnay]

Could you move the main function out of the root module and provide an empty main instead? If not, I think you may be able to bypass main as the entry point by adding:

#![feature(start)]

#[start]
fn start(_argc: isize, _argv: *const *const u8) -> isize {
    0
}

[davidbarsky]

Could you move the main function out of the root module and provide an empty main instead?

Not really; the procedural macro I'm testing (#[lambda]) is intended to be invoked in normal usage as:

#![feature(async_await)]

use lambda::{lambda, Error};

#[lambda]
#[runtime::main]
async fn main(s: String) -> Result<String, Error> {
    Ok(s)
}

If not, I think you may be able to bypass main as the entry point by adding: [code redacted]

Thanks! That did the trick with:

#![feature(async_await, start)]

use lambda::{lambda, Error};

#[lambda]
#[runtime::main]
async fn main(s: String) -> Result<String, Error> {
    Ok(s)
}

#[start]
fn start(_argc: isize, _argv: *const *const u8) -> isize {
    0
}

Bit curious—why does Trybuild execute the procedural macro instead of only building?

[slinkydeveloper]

I had the same problem (i was generating the main method too), fixed adding start method.