103 lines
2.6 KiB
Rust
103 lines
2.6 KiB
Rust
//! Note
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//! ----
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//! You're probably viewing this file because you're adding a test (or you might
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//! just be browsing, in that case, hey there!).
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//!
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//! The iter test suite is split into two big modules, and some miscellaneous
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//! smaller modules. The two big modules are `adapters` and `traits`.
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//!
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//! `adapters` are for methods on `Iterator` that adapt the data inside the
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//! iterator, whether it be by emitting another iterator or returning an item
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//! from inside the iterator after executing a closure on each item.
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//!
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//! `traits` are for trait's that extend an `Iterator` (and the `Iterator`
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//! trait itself, mostly containing miscellaneous methods). For the most part,
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//! if a test in `traits` uses a specific adapter, then it should be moved to
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//! that adapter's test file in `adapters`.
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mod adapters;
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mod range;
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mod sources;
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mod traits;
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use core::cell::Cell;
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use core::convert::TryFrom;
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use core::iter::*;
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pub fn is_trusted_len<I: TrustedLen>(_: I) {}
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#[test]
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fn test_multi_iter() {
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let xs = [1, 2, 3, 4];
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let ys = [4, 3, 2, 1];
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assert!(xs.iter().eq(ys.iter().rev()));
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assert!(xs.iter().lt(xs.iter().skip(2)));
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}
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#[test]
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fn test_counter_from_iter() {
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let it = (0..).step_by(5).take(10);
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let xs: Vec<isize> = FromIterator::from_iter(it);
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assert_eq!(xs, [0, 5, 10, 15, 20, 25, 30, 35, 40, 45]);
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}
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#[test]
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fn test_functor_laws() {
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// identity:
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fn identity<T>(x: T) -> T {
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x
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}
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assert_eq!((0..10).map(identity).sum::<usize>(), (0..10).sum());
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// composition:
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fn f(x: usize) -> usize {
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x + 3
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}
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fn g(x: usize) -> usize {
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x * 2
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}
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fn h(x: usize) -> usize {
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g(f(x))
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}
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assert_eq!((0..10).map(f).map(g).sum::<usize>(), (0..10).map(h).sum());
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}
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#[test]
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fn test_monad_laws_left_identity() {
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fn f(x: usize) -> impl Iterator<Item = usize> {
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(0..10).map(move |y| x * y)
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}
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assert_eq!(once(42).flat_map(f.clone()).sum::<usize>(), f(42).sum());
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}
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#[test]
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fn test_monad_laws_right_identity() {
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assert_eq!((0..10).flat_map(|x| once(x)).sum::<usize>(), (0..10).sum());
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}
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#[test]
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fn test_monad_laws_associativity() {
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fn f(x: usize) -> impl Iterator<Item = usize> {
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0..x
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}
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fn g(x: usize) -> impl Iterator<Item = usize> {
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(0..x).rev()
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}
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assert_eq!(
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(0..10).flat_map(f).flat_map(g).sum::<usize>(),
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(0..10).flat_map(|x| f(x).flat_map(g)).sum::<usize>()
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);
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}
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#[test]
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pub fn extend_for_unit() {
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let mut x = 0;
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{
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let iter = (0..5).map(|_| {
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x += 1;
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});
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().extend(iter);
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}
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assert_eq!(x, 5);
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}
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