1.6 Testing : Test should pass rather than fail

Inizia con il tutorial sui test collegato nell’issue e con il test CLI mostrato, quindi esegui cargo test --test cli per riprodurre la discrepanza. Confronta l’asserzione con lo stderr riportato dal comando e modifica l’esempio in modo che il test corrisponda all’errore documentato; il lavoro è concluso quando il test segnala un test superato.

Below test with more description can be found at

use assert_cmd::prelude::*; // Add methods on commands
use predicates::prelude::*; // Used for writing assertions
use std::process::Command; // Run programs

#[test]
fn file_doesnt_exist() -> Result<(), Box<dyn std::error::Error>> {
    let mut cmd = Command::cargo_bin("grrs")?;

    cmd.arg("foobar").arg("test/file/doesnt/exist");
    cmd.assert()
        .failure()
        .stderr(predicate::str::contains("could not read file"));

    Ok(())
}

My Expectation:
grss rightly throws the exception when file does not exist. This test should capture the exception and should be pass as it has captured the right exception. But on running 'cargo test', this test is reported as failure.

Current Result:
test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 1.55s
IMO Expected Result
test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 1.55s

Output of cargo test:
` Running tests/cli.rs (target/debug/deps/cli-5cefbff21b07bd9f)

running 1 test
test file_doesnt_exist ... FAILED

failures:

---- file_doesnt_exist stdout ----
thread 'file_doesnt_exist' panicked at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/core/src/ops/function.rs:250:5:
Unexpected stderr, failed var.contains(could not read file)
├── var: Error: Could not read file 'test/file/doesnt/exists'
│
│ Caused by:
│ No such file or directory (os error 2)
└── var as str: Error: Could not read file 'test/file/doesnt/exists'

Caused by:
    No such file or directory (os error 2)

command="/Users/admin/Kishor/SxT/repos/grrs/target/debug/grrs" "foobar" "test/file/doesnt/exists"
code=1
stdout=""
stderr=```
Error: Could not read file 'test/file/doesnt/exists'

Caused by:
No such file or directory (os error 2)

note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


failures:
    file_doesnt_exist

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 1.55s

error: test failed, to rerun pass `--test cli`
`