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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /library/core/tests/iter/adapters/intersperse.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | library/core/tests/iter/adapters/intersperse.rs | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/library/core/tests/iter/adapters/intersperse.rs b/library/core/tests/iter/adapters/intersperse.rs new file mode 100644 index 000000000..72ae59b6b --- /dev/null +++ b/library/core/tests/iter/adapters/intersperse.rs @@ -0,0 +1,154 @@ +use core::iter::*; + +#[test] +fn test_intersperse() { + let v = std::iter::empty().intersperse(0u32).collect::<Vec<_>>(); + assert_eq!(v, vec![]); + + let v = std::iter::once(1).intersperse(0).collect::<Vec<_>>(); + assert_eq!(v, vec![1]); + + let xs = ["a", "", "b", "c"]; + let v: Vec<&str> = xs.iter().map(|x| *x).intersperse(", ").collect(); + let text: String = v.concat(); + assert_eq!(text, "a, , b, c".to_string()); + + let ys = [0, 1, 2, 3]; + let mut it = ys[..0].iter().map(|x| *x).intersperse(1); + assert!(it.next() == None); +} + +#[test] +fn test_intersperse_size_hint() { + let iter = std::iter::empty::<i32>().intersperse(0); + assert_eq!(iter.size_hint(), (0, Some(0))); + + let xs = ["a", "", "b", "c"]; + let mut iter = xs.iter().map(|x| *x).intersperse(", "); + assert_eq!(iter.size_hint(), (7, Some(7))); + + assert_eq!(iter.next(), Some("a")); + assert_eq!(iter.size_hint(), (6, Some(6))); + assert_eq!(iter.next(), Some(", ")); + assert_eq!(iter.size_hint(), (5, Some(5))); + + assert_eq!([].iter().intersperse(&()).size_hint(), (0, Some(0))); +} + +#[test] +fn test_fold_specialization_intersperse() { + let mut iter = (1..2).intersperse(0); + iter.clone().for_each(|x| assert_eq!(Some(x), iter.next())); + + let mut iter = (1..3).intersperse(0); + iter.clone().for_each(|x| assert_eq!(Some(x), iter.next())); + + let mut iter = (1..4).intersperse(0); + iter.clone().for_each(|x| assert_eq!(Some(x), iter.next())); +} + +#[test] +fn test_try_fold_specialization_intersperse_ok() { + let mut iter = (1..2).intersperse(0); + iter.clone().try_for_each(|x| { + assert_eq!(Some(x), iter.next()); + Some(()) + }); + + let mut iter = (1..3).intersperse(0); + iter.clone().try_for_each(|x| { + assert_eq!(Some(x), iter.next()); + Some(()) + }); + + let mut iter = (1..4).intersperse(0); + iter.clone().try_for_each(|x| { + assert_eq!(Some(x), iter.next()); + Some(()) + }); +} + +#[test] +fn test_intersperse_with() { + #[derive(PartialEq, Debug)] + struct NotClone { + u: u32, + } + let r = [NotClone { u: 0 }, NotClone { u: 1 }] + .into_iter() + .intersperse_with(|| NotClone { u: 2 }) + .collect::<Vec<_>>(); + assert_eq!(r, vec![NotClone { u: 0 }, NotClone { u: 2 }, NotClone { u: 1 }]); + + let mut ctr = 100; + let separator = || { + ctr *= 2; + ctr + }; + let r = (0..3).intersperse_with(separator).collect::<Vec<_>>(); + assert_eq!(r, vec![0, 200, 1, 400, 2]); +} + +#[test] +fn test_intersperse_fold() { + let v = (1..4).intersperse(9).fold(Vec::new(), |mut acc, x| { + acc.push(x); + acc + }); + assert_eq!(v.as_slice(), [1, 9, 2, 9, 3]); + + let mut iter = (1..4).intersperse(9); + assert_eq!(iter.next(), Some(1)); + let v = iter.fold(Vec::new(), |mut acc, x| { + acc.push(x); + acc + }); + assert_eq!(v.as_slice(), [9, 2, 9, 3]); + + struct NoneAtStart(i32); // Produces: None, Some(2), Some(3), None, ... + impl Iterator for NoneAtStart { + type Item = i32; + fn next(&mut self) -> Option<i32> { + self.0 += 1; + Some(self.0).filter(|i| i % 3 != 1) + } + } + + let v = NoneAtStart(0).intersperse(1000).fold(0, |a, b| a + b); + assert_eq!(v, 0); +} + +#[test] +fn test_intersperse_collect_string() { + let contents = [1, 2, 3]; + + let contents_string = contents + .into_iter() + .map(|id| id.to_string()) + .intersperse(", ".to_owned()) + .collect::<String>(); + assert_eq!(contents_string, "1, 2, 3"); +} + +#[test] +fn test_try_fold_specialization_intersperse_err() { + let orig_iter = ["a", "b"].iter().copied().intersperse("-"); + + // Abort after the first item. + let mut iter = orig_iter.clone(); + iter.try_for_each(|_| None::<()>); + assert_eq!(iter.next(), Some("-")); + assert_eq!(iter.next(), Some("b")); + assert_eq!(iter.next(), None); + + // Abort after the second item. + let mut iter = orig_iter.clone(); + iter.try_for_each(|item| if item == "-" { None } else { Some(()) }); + assert_eq!(iter.next(), Some("b")); + assert_eq!(iter.next(), None); + + // Abort after the third item. + let mut iter = orig_iter.clone(); + iter.try_for_each(|item| if item == "b" { None } else { Some(()) }); + assert_eq!(iter.next(), None); +} |