Macro assertables::assert_fn_eq

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

Assert one function output is equal to another function output.

• When true, return ().

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

Example

assert_fn_eq!(i32::abs, 1 as i32, -1 as i32);
//-> ()

// assert_fn_eq!(i32::abs, 1 as i32, -2 as i32);
//-> panic!("assertion failed: `assert_fn_eq(fn, left, right)`\n  left input: `1`\n right input: `2`\n  left output: `1`\n right output: `2`")

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