Macro deltae::assert_delta_eq

macro_rules! assert_delta_eq {
    ($reference : expr, $sample : expr, $method : expr, $tolerance : expr) => { ... };
    ($reference : expr, $sample : expr, $method : expr, $tolerance : expr,
 $($message : tt) *) => { ... };
}

Convenience macro for asserting two values are equivalent within a tolerance

use deltae::*;

let lab0 = LabValue::new(50.0, 0.0, 0.0).unwrap();
let lab1 = LabValue::new(50.1, 0.1, 0.1).unwrap();

// Assert that the difference between lab0 and lab1 is less than 1.0 DE2000
assert_delta_eq!(lab0, lab1, DE2000, 1.0);