use run_make_support::bare_rustc; fn main() { let signalled_version = "Ceci n'est pas une rustc"; let rustc_out = bare_rustc() .env("RUSTC_OVERRIDE_VERSION_STRING", signalled_version) .arg("--version") .run() .stdout_utf8(); let version = rustc_out.strip_prefix("rustc ").unwrap().trim_end(); assert_eq!(version, signalled_version); }