Macro assertables::assert_fn_ok_eq

macro_rules! assert_fn_ok_eq {
    ($function:path, $a_input:expr, $b_expr:expr $(,)?) => { ... };
    ($function:path, $a_input:expr, $b_expr:expr, $($arg:tt)+) => { ... };
}

Assert a function ok() is 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: i32) -> Result<String, String> {
    match i {
        0..=9 => Ok(format!("{}", i)),
        _ => Err(format!("{:?} is out of range", i)),
    }
}

let a = 1;
let b = String::from("1");
assert_fn_ok_eq!(example_digit_to_string, a, b);
//-> ()

let a = 1;
let b = String::from("2");
let result = panic::catch_unwind(|| {
assert_fn_ok_eq!(example_digit_to_string, a, b);
//-> panic!
});
let actual = result.unwrap_err().downcast::<String>().unwrap().to_string();
let expect = concat!(
    "assertion failed: `assert_fn_ok_eq!(function, left_input, right_expr)`\n",
    "    function name: `example_digit_to_string`,\n",
    "  left input name: `a`,\n",
    "  right expr name: `b`,\n",
    "       left input: `1`,\n",
    "       right expr: `\"2\"`,\n",
    "      left output: `\"1\"`,\n",
    "             left: `\"1\"`,\n",
    "            right: `\"2\"`"
);
assert_eq!(actual, expect);