Unable to find the test name for unit tests, in release mode, with test-threads=1

[zazabe]

insta is not able to find the test name for unit tests, in release mode, with --test-threads=1 option, even with the "backtrace" feature.

main.rs

#[test]
fn test_snapshot() {
    insta::assert_snapshot!("foo", @"foo");
}

Cargo.toml

[...]
[dependencies]
insta = { version = "0.15.0", features = ["backtrace"] }

test result:

$ cargo test --release --quiet -- --test-threads=1

running 1 test
F
failures:

---- test_snapshot stdout ----
thread 'main' panicked at 'Cannot determine test name from backtrace, no snapshot name can be generated.', /home/user/.cargo/registry/src/github.com-1ecc6299db9ec823/insta-0.15.0/src/runtime.rs:503:5
[...]

[zazabe]

I opened this ticket for the record, feel free to close.

Workaround

A workaround is to override the debug setting of the bench profile, used by cargo test --release:

Cargo.toml

[...]
[dependencies]
insta = { version = "0.15.0", features = ["backtrace"] }

[profile.bench]
debug = 1 # line tables only

test result:

$ cargo test --release --quiet -- --test-threads=1

running 1 test
.
test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

[mitsuhiko]

Unfortunately there is nothing I can do about this with the tools available currently. It might be worth filing a feature request for rust-test.

[mitsuhiko]

I filed an issue here: rust-lang/rust#70492