Macro assertables::assert_fn_eq_other

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

Assert a function output is equal to another.

• If true, return ().

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

Examples

let a: i32 = -1;
let b: i32 = 1;
assert_fn_eq_other!(i32::abs, a, b);
//-> ()

let result = panic::catch_unwind(|| {
let a: i32 = 1;
let b: i32 = -2;
assert_fn_eq_other!(i32::abs, a, b);
//-> panic!
});
let actual = result.unwrap_err().downcast::<String>().unwrap().to_string();
let expect = concat!(
    "assertion failed: `assert_fn_eq_other!(pair_function, left_input, right_input)`\n",
    " pair_function label: `i32::abs`,\n",
    "    left_input label: `a`,\n",
    "    left_input debug: `1`,\n",
    "   right_input label: `b`,\n",
    "   right_input debug: `-2`,\n",
    "                left: `1`,\n",
    "               right: `2`"
);
assert_eq!(actual, expect);