Fix: Add missing negation

If we emit a ReadUntil::NBytes, but the `eof` flag is already set and
the buffer is indeed _not_ empty, we return Some() here. If the buffer
is empty, there's nothing to return, so we return None.

This fixes the following tests:

* reader::tests::test_any_with_multiple_possible_matches
* reader::tests::test_any_with_same_start_different_length
* reader::tests::test_eof
* reader::tests::test_expect_melon
* reader::tests::test_nbytes
* reader::tests::test_regex
* reader::tests::test_regex2

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

Author: matthiasbeyer

src/reader.rs

@@ -75,7 +75,7 @@ pub fn find(needle: &ReadUntil, buffer: &str, eof: bool) -> Option<(usize, usize
         ReadUntil::NBytes(n) => {
             if *n <= buffer.len() {
                 Some((0, *n))
-            } else if eof && buffer.is_empty() {
+            } else if eof && !buffer.is_empty() {
                 // reached almost end of buffer, return string, even though it will be
                 // smaller than the wished n bytes
                 Some((0, buffer.len()))