Macro assert_needed 

macro_rules! assert_needed {
    ($e:expr $(,)?) => { ... };
    ($e:expr, $($arg:tt)+) => { ... };
}

This asserts that the IResult is an Incomplete

Examples

use std::num::NonZeroUsize;
use nom_test_helpers::assert_needed;
use nom::Needed;

let r: nom::IResult<&[u8], &[u8]> = Err(nom::Err::Incomplete(Needed::Size(NonZeroUsize::new(1).unwrap())));
assert_needed!(r);