Assert an expression is Err and its value is equal to an expression.
Pseudocode: (a ⇒ Err(a1) ⇒ a1) = b
use assertables::*; let a: Result<i8, i8> = Err(1); let b: i8 = 1; assert_err_eq_x!(a, b);
assert_err_eq_x
assert_err_eq_x_as_result
debug_assert_err_eq_x