Macro cgmath::assert_relative_eq

macro_rules! assert_relative_eq {
    ($ given : expr, $ expected : expr $ (, $ opt : ident = $ val : expr) *) => { ... };
    ($ given : expr, $ expected : expr $ (, $ opt : ident = $ val : expr) *,) => { ... };
}

An assertion that delegates to relative_eq!, and panics with a helpful error on failure.