Assert a function output is not equal to another.
Pseudocode: a_function(a) ≠ b_function(b)
use assertables::*; let a: i8 = -1; let b: i8 = 2; assert_fn_ne!(i8::abs, a, i8::abs, b);
assert_fn_ne
assert_fn_ne_as_result
debug_assert_fn_ne