Module approx_eq

Macro to test that two values are approximately equal. It checks that the relative difference between the two values is less than some epsilon value.

use approx_eq::assert_approx_eq;
fn main() {
  assert_approx_eq!(1., 0.99999999999); // should pass
  assert_approx_eq!(1., 0.99999999999, 1e-5); // should pass
  assert_approx_eq!(1., 0.99999999999, 1e-20); // should fail
  assert_approx_eq!(0., 0.); // should pass
  assert_approx_eq!(1., 2.); // should fail
}