Macro assertables::assert_f_err_string_ne

macro_rules! assert_f_err_string_ne {
    ($function:path, $left:expr, $right:expr $(,)?) => { ... };
    ($function:path, $left:expr, $right:expr, $($arg:tt)+) => { ... };
}

Assert a function err() is not equal to another.

• When true, return ().

• Otherwise, call panic! with a message and the values of the expressions with their debug representations.

Examples

fn example_digit_to_string(i: isize) -> Result<String, String> {
    match i {
        0..=9 => Ok(format!("{}", i)),
        _ => Err(format!("{:?} is out of range", i)),
    }
}

assert_f_err_string_ne!(example_digit_to_string, 10, 20);
//-> ()

assert_f_err_string_ne!(example_digit_to_string, 10, 10);
//-> panic!("…")
// assertion failed: `assert_f_err_string_ne!(function, left, right)`
//    left input: `10`,
//   right input: `10`,
//   left output: `\"10 is out of range\"`,
//  right output: `\"10 is out of range\"`

This macro has a second form where a custom message can be provided.