Fuzed iterator
fuzed-iterator
is a Rust library crate that provides a simple iterator wrapper
that causes a panic if the iterator is used after it has once returned None
.
Many iterators in std
implement the FusedIterator
trait, which
guarantees that the iterator will never return Some
after returning None
.
This may make programmers incorrectly assume that any iterator works like a
FusedIterator
, leading to bugs when a non-fused iterator is used.
The Fuze
wrapper provided by this crate can be used to wrap any iterator,
causing a panic if the iterator is used after returning None
for the first
time. This can be used to catch bugs where a non-fused iterator is used in a
context where a fused iterator is expected. In your unit tests (or integration
tests), pass iterators through Fuze
to your functions that expect an iterator
(not necessarily fused), and the tests will panic if the function calls
Iterator::next
excessively.
Example
use IteratorExt as _;
let mut iter = .fuze;
assert_eq!;
assert_eq!;
assert_eq!;
assert_eq!;
iter.next; // Another `next` call would panic!
/// Collects items from an iterator into a vector, but drops the first item.
// Because of the wrong implementation, this test case would fail with a panic.
# /*
#[test]
# */
# test_drop_first_and_collect_with_empty_array;
/// Collects items from an iterator into a vector, but drops the first item.
// Test passed!
# /*
#[test]
# */
# test_drop_first_and_collect_with_empty_array;
License
MIT or Apache 2.0, at your option