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Diffstat (limited to '')
-rw-r--r-- | library/core/tests/iter/adapters/filter.rs | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/library/core/tests/iter/adapters/filter.rs b/library/core/tests/iter/adapters/filter.rs new file mode 100644 index 000000000..a2050d89d --- /dev/null +++ b/library/core/tests/iter/adapters/filter.rs @@ -0,0 +1,52 @@ +use core::iter::*; + +#[test] +fn test_iterator_filter_count() { + let xs = [0, 1, 2, 3, 4, 5, 6, 7, 8]; + assert_eq!(xs.iter().filter(|&&x| x % 2 == 0).count(), 5); +} + +#[test] +fn test_iterator_filter_fold() { + let xs = [0, 1, 2, 3, 4, 5, 6, 7, 8]; + let ys = [0, 2, 4, 6, 8]; + let it = xs.iter().filter(|&&x| x % 2 == 0); + let i = it.fold(0, |i, &x| { + assert_eq!(x, ys[i]); + i + 1 + }); + assert_eq!(i, ys.len()); + + let it = xs.iter().filter(|&&x| x % 2 == 0); + let i = it.rfold(ys.len(), |i, &x| { + assert_eq!(x, ys[i - 1]); + i - 1 + }); + assert_eq!(i, 0); +} + +#[test] +fn test_filter_try_folds() { + fn p(&x: &i32) -> bool { + 0 <= x && x < 10 + } + let f = &|acc, x| i32::checked_add(2 * acc, x); + assert_eq!((-10..20).filter(p).try_fold(7, f), (0..10).try_fold(7, f)); + assert_eq!((-10..20).filter(p).try_rfold(7, f), (0..10).try_rfold(7, f)); + + let mut iter = (0..40).filter(|&x| x % 2 == 1); + assert_eq!(iter.try_fold(0, i8::checked_add), None); + assert_eq!(iter.next(), Some(25)); + assert_eq!(iter.try_rfold(0, i8::checked_add), None); + assert_eq!(iter.next_back(), Some(31)); +} + +#[test] +fn test_double_ended_filter() { + let xs = [1, 2, 3, 4, 5, 6]; + let mut it = xs.iter().filter(|&x| *x & 1 == 0); + assert_eq!(it.next_back().unwrap(), &6); + assert_eq!(it.next_back().unwrap(), &4); + assert_eq!(it.next().unwrap(), &2); + assert_eq!(it.next_back(), None); +} |