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Diffstat (limited to 'library/core/tests/iter/traits/double_ended.rs')
-rw-r--r-- | library/core/tests/iter/traits/double_ended.rs | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/library/core/tests/iter/traits/double_ended.rs b/library/core/tests/iter/traits/double_ended.rs new file mode 100644 index 000000000..00ef4a6e6 --- /dev/null +++ b/library/core/tests/iter/traits/double_ended.rs @@ -0,0 +1,91 @@ +//! Note +//! ---- +//! You're probably viewing this file because you're adding a test (or you might +//! just be browsing, in that case, hey there!). +//! +//! If you've made a test that happens to use one of DoubleEnded's methods, but +//! it tests another adapter or trait, you should *add it to the adapter or +//! trait's test file*. +//! +//! Some examples would be `adapters::cloned::test_cloned_try_folds` or +//! `adapters::flat_map::test_double_ended_flat_map`, which use `try_fold` and +//! `next_back`, but test their own adapter. + +#[test] +fn test_iterator_rev_nth_back() { + let v: &[_] = &[0, 1, 2, 3, 4]; + for i in 0..v.len() { + assert_eq!(v.iter().rev().nth_back(i).unwrap(), &v[i]); + } + assert_eq!(v.iter().rev().nth_back(v.len()), None); +} + +#[test] +fn test_iterator_rev_nth() { + let v: &[_] = &[0, 1, 2, 3, 4]; + for i in 0..v.len() { + assert_eq!(v.iter().rev().nth(i).unwrap(), &v[v.len() - 1 - i]); + } + assert_eq!(v.iter().rev().nth(v.len()), None); +} + +#[test] +fn test_rev() { + let xs = [2, 4, 6, 8, 10, 12, 14, 16]; + let mut it = xs.iter(); + it.next(); + it.next(); + assert!(it.rev().cloned().collect::<Vec<isize>>() == vec![16, 14, 12, 10, 8, 6]); +} + +#[test] +fn test_rev_try_folds() { + let f = &|acc, x| i32::checked_add(2 * acc, x); + assert_eq!((1..10).rev().try_fold(7, f), (1..10).try_rfold(7, f)); + assert_eq!((1..10).rev().try_rfold(7, f), (1..10).try_fold(7, f)); + + let a = [10, 20, 30, 40, 100, 60, 70, 80, 90]; + let mut iter = a.iter().rev(); + assert_eq!(iter.try_fold(0_i8, |acc, &x| acc.checked_add(x)), None); + assert_eq!(iter.next(), Some(&70)); + let mut iter = a.iter().rev(); + assert_eq!(iter.try_rfold(0_i8, |acc, &x| acc.checked_add(x)), None); + assert_eq!(iter.next_back(), Some(&60)); +} + +#[test] +fn test_rposition() { + fn f(xy: &(isize, char)) -> bool { + let (_x, y) = *xy; + y == 'b' + } + fn g(xy: &(isize, char)) -> bool { + let (_x, y) = *xy; + y == 'd' + } + let v = [(0, 'a'), (1, 'b'), (2, 'c'), (3, 'b')]; + + assert_eq!(v.iter().rposition(f), Some(3)); + assert!(v.iter().rposition(g).is_none()); +} + +#[test] +fn test_rev_rposition() { + let v = [0, 0, 1, 1]; + assert_eq!(v.iter().rev().rposition(|&x| x == 1), Some(1)); +} + +#[test] +#[should_panic] +fn test_rposition_panic() { + let u = (Box::new(0), Box::new(0)); + let v: [(Box<_>, Box<_>); 4] = [u.clone(), u.clone(), u.clone(), u]; + let mut i = 0; + v.iter().rposition(|_elt| { + if i == 2 { + panic!() + } + i += 1; + false + }); +} |