#[should_panic] ignores function-like macros

[dylni]

I tried this code:

#[cfg(test)]
mod tests {
    #[test]
    #[should_panic = concat!("a")]
    fn test() {
        panic!("b");
    }
}

fn main() {}

https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=1268154aa9d34acf6833b9affa7e6b81

I expected to see this happen:

running 1 test
test tests::test - should panic ... FAILED

failures:

---- tests::test stdout ----
thread 'tests::test' panicked at 'b', src/lib.rs:6:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
note: panic did not contain expected string
      panic message: `"b"`,
 expected substring: `"a"`

failures:
    tests::test

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

Instead, this happened:

running 1 test
test tests::test - should panic ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s


running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

Changing concat!("a") to "a" shows the expected error:
https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=e0aa41c95b4cd19e82332b6f030987f5

[dylni]

@rustbot modify labels +A-libtest

[edmorley]

I encountered this too.

My use-case is wanting to test a panic error message that contains an absolute path (which must be absolute due to the nature of what the error is trying to convey) which will vary based on what machine ran the test.

Since should_panic does not support globs/regex, I'm not able to test the whole error message, only the part up to the absolute path (or the part after it, but not both).

If function-like macros were supported here, I could use concat! + env!("CARGO_MANIFEST_DIR") etc to construct the absolute path in should_match's expected value.