tests fail with panic

[ecausarano]

Hi,

running rustlings watch causes all exercises with a test to fail with no output

⚠️  Testing of exercises/if/if1.rs failed! Please try again. Here's the output:

Running with `cargo test' produces the following output:

---- exercise::test::test_exercise_with_output stdout ----
thread 'exercise::test::test_exercise_with_output' panicked at 'called `Result::unwrap()` on an `Err` value: ExerciseOutput { stdout: "", stderr: "error: Unrecognized option: \'show-output\'\n" }', src/libcore/result.rs:1084:5

rustc --version
rustc 1.38.0 (625451e37 2019-09-23)

rustlings --version
rustlings 4.1.0

on macOS Catalina 10.15.7 (19H2)

[seeplusplus]

This looks to be due to the fact that show-output was introduced in rust 1.39.0:
rust-lang/rust#62600

Since running rustlings watch causes verify, this will execute the exercise in test mode (supplying --show-output).

Related: #422

[ecausarano]

Oh, that's odd... despite updating rust from brew it still reports 'rustc 1.38.0 (625451e37 2019-09-23)'.
I suspect I must have installed rust from a standalone package some time ago.

Perhaps rustlings could add a warning (or error-out) on an old enough version?

edit1: @seeplusplus - indeed an outdated install was the issue, thanks for pointing that out!