use super::*; use core::iter::*; #[test] fn test_repeat() { let mut it = repeat(42); assert_eq!(it.next(), Some(42)); assert_eq!(it.next(), Some(42)); assert_eq!(it.next(), Some(42)); assert_eq!(repeat(42).size_hint(), (usize::MAX, None)); } #[test] fn test_repeat_take() { let mut it = repeat(42).take(3); assert_eq!(it.next(), Some(42)); assert_eq!(it.next(), Some(42)); assert_eq!(it.next(), Some(42)); assert_eq!(it.next(), None); is_trusted_len(repeat(42).take(3)); assert_eq!(repeat(42).take(3).size_hint(), (3, Some(3))); assert_eq!(repeat(42).take(0).size_hint(), (0, Some(0))); assert_eq!(repeat(42).take(usize::MAX).size_hint(), (usize::MAX, Some(usize::MAX))); } #[test] fn test_repeat_take_collect() { let v: Vec<_> = repeat(42).take(3).collect(); assert_eq!(v, vec![42, 42, 42]); } #[test] fn test_repeat_with() { #[derive(PartialEq, Debug)] struct NotClone(usize); let mut it = repeat_with(|| NotClone(42)); assert_eq!(it.next(), Some(NotClone(42))); assert_eq!(it.next(), Some(NotClone(42))); assert_eq!(it.next(), Some(NotClone(42))); assert_eq!(repeat_with(|| NotClone(42)).size_hint(), (usize::MAX, None)); } #[test] fn test_repeat_with_take() { let mut it = repeat_with(|| 42).take(3); assert_eq!(it.next(), Some(42)); assert_eq!(it.next(), Some(42)); assert_eq!(it.next(), Some(42)); assert_eq!(it.next(), None); is_trusted_len(repeat_with(|| 42).take(3)); assert_eq!(repeat_with(|| 42).take(3).size_hint(), (3, Some(3))); assert_eq!(repeat_with(|| 42).take(0).size_hint(), (0, Some(0))); assert_eq!(repeat_with(|| 42).take(usize::MAX).size_hint(), (usize::MAX, Some(usize::MAX))); } #[test] fn test_repeat_with_take_collect() { let mut curr = 1; let v: Vec<_> = repeat_with(|| { let tmp = curr; curr *= 2; tmp }) .take(5) .collect(); assert_eq!(v, vec![1, 2, 4, 8, 16]); } #[test] fn test_successors() { let mut powers_of_10 = successors(Some(1_u16), |n| n.checked_mul(10)); assert_eq!(powers_of_10.by_ref().collect::>(), &[1, 10, 100, 1_000, 10_000]); assert_eq!(powers_of_10.next(), None); let mut empty = successors(None::, |_| unimplemented!()); assert_eq!(empty.next(), None); assert_eq!(empty.next(), None); } #[test] fn test_once() { let mut it = once(42); assert_eq!(it.next(), Some(42)); assert_eq!(it.next(), None); } #[test] fn test_once_with() { let count = Cell::new(0); let mut it = once_with(|| { count.set(count.get() + 1); 42 }); assert_eq!(count.get(), 0); assert_eq!(it.next(), Some(42)); assert_eq!(count.get(), 1); assert_eq!(it.next(), None); assert_eq!(count.get(), 1); assert_eq!(it.next(), None); assert_eq!(count.get(), 1); } #[test] fn test_empty() { let mut it = empty::(); assert_eq!(it.next(), None); }