From de8c79a53532c4a6de61b0dcde6ed9b133afa752 Mon Sep 17 00:00:00 2001 From: Steven Allen Date: Wed, 22 Apr 2015 16:03:56 -0400 Subject: Implement O(1) slice::Iter methods. Instead of using the O(n) defaults, define O(1) shortcuts. --- src/libcoretest/slice.rs | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'src/libcoretest') diff --git a/src/libcoretest/slice.rs b/src/libcoretest/slice.rs index fe73b3b4407..7c884a73ce0 100644 --- a/src/libcoretest/slice.rs +++ b/src/libcoretest/slice.rs @@ -82,3 +82,34 @@ fn iterator_to_slice() { test!([1u8,2,3]); test!([(),(),()]); } + +#[test] +fn test_iterator_nth() { + let v: &[_] = &[0, 1, 2, 3, 4]; + for i in 0..v.len() { + assert_eq!(v.iter().nth(i).unwrap(), &v[i]); + } + assert_eq!(v.iter().nth(v.len()), None); + + let mut iter = v.iter(); + assert_eq!(iter.nth(2).unwrap(), &v[2]); + assert_eq!(iter.nth(1).unwrap(), &v[4]); +} + +#[test] +fn test_iterator_last() { + let v: &[_] = &[0, 1, 2, 3, 4]; + assert_eq!(v.iter().last().unwrap(), &4); + assert_eq!(v[..1].iter().last().unwrap(), &0); +} + +#[test] +fn test_iterator_count() { + let v: &[_] = &[0, 1, 2, 3, 4]; + assert_eq!(v.iter().count(), 5); + + let mut iter2 = v.iter(); + iter2.next(); + iter2.next(); + assert_eq!(iter2.count(), 3); +} -- cgit 1.4.1-3-g733a5