hodoku

A simple set of macros to aid testing with try operations.

This crate allows for easily writing functions and expression where ? is automatically translated into .unwrap().

It is syntactically desirable to use ?. This however causes issues during testing, because a failing test lacks a stack trace which helps you track down the exact line that errored.

#[test]
fn test_case() -> Result<(), &'static str> {
    let value = function()?;
    assert_eq!(value, 42);
    Ok(())
}

By default you'd get this when function()? errors:

---- test_case stdout ----
Error: "bad"
thread 'test_case' panicked at 'assertion failed: `(left == right)`
  left: `1`,
 right: `0`: the test returned a termination value with a non-zero status code (1) which indicates a failure', <path>\library\test\src\lib.rs:185:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


failures:
    test_case

Note how there's no information on which line the test failed on.

But with the inclusion of #[hodoku::function] you get this:

#[test]
#[hodoku::function]
fn test_case() -> Result<(), &'static str> {
    let value = function()?;
    assert_eq!(value, 42);
    Ok(())
}

---- test_case stdout ----
thread 'test_case' panicked at 'called `Result::unwrap()` on an `Err` value: "bad"', tests\failing.rs:8:27
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


failures:
    test_case

This is exactly why we want to make use of .unwrap() instead of the try operator tests. It indicates the exact line that errored.

Examples

Use of #[hodoku::function].

#[hodoku::function]
fn hello() {
    let value = Some(42)?;
    assert_eq!(value, 42);
}

hello();

Unwrapping expressions:

let value = hodoku::expr!(Some(42)?);
assert_eq!(value, 42);