use core::iter::*; #[test] fn test_iterator_sum() { let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; assert_eq!(v[..4].iter().cloned().sum::<i32>(), 6); assert_eq!(v.iter().cloned().sum::<i32>(), 55); assert_eq!(v[..0].iter().cloned().sum::<i32>(), 0); } #[test] fn test_iterator_sum_result() { let v: &[Result<i32, ()>] = &[Ok(1), Ok(2), Ok(3), Ok(4)]; assert_eq!(v.iter().cloned().sum::<Result<i32, _>>(), Ok(10)); let v: &[Result<i32, ()>] = &[Ok(1), Err(()), Ok(3), Ok(4)]; assert_eq!(v.iter().cloned().sum::<Result<i32, _>>(), Err(())); #[derive(PartialEq, Debug)] struct S(Result<i32, ()>); impl Sum<Result<i32, ()>> for S { fn sum<I: Iterator<Item = Result<i32, ()>>>(mut iter: I) -> Self { // takes the sum by repeatedly calling `next` on `iter`, // thus testing that repeated calls to `ResultShunt::try_fold` // produce the expected results Self(iter.by_ref().sum()) } } let v: &[Result<i32, ()>] = &[Ok(1), Ok(2), Ok(3), Ok(4)]; assert_eq!(v.iter().cloned().sum::<S>(), S(Ok(10))); let v: &[Result<i32, ()>] = &[Ok(1), Err(()), Ok(3), Ok(4)]; assert_eq!(v.iter().cloned().sum::<S>(), S(Err(()))); } #[test] fn test_iterator_sum_option() { let v: &[Option<i32>] = &[Some(1), Some(2), Some(3), Some(4)]; assert_eq!(v.iter().cloned().sum::<Option<i32>>(), Some(10)); let v: &[Option<i32>] = &[Some(1), None, Some(3), Some(4)]; assert_eq!(v.iter().cloned().sum::<Option<i32>>(), None); } #[test] fn test_iterator_product() { let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; assert_eq!(v[..4].iter().cloned().product::<i32>(), 0); assert_eq!(v[1..5].iter().cloned().product::<i32>(), 24); assert_eq!(v[..0].iter().cloned().product::<i32>(), 1); } #[test] fn test_iterator_product_result() { let v: &[Result<i32, ()>] = &[Ok(1), Ok(2), Ok(3), Ok(4)]; assert_eq!(v.iter().cloned().product::<Result<i32, _>>(), Ok(24)); let v: &[Result<i32, ()>] = &[Ok(1), Err(()), Ok(3), Ok(4)]; assert_eq!(v.iter().cloned().product::<Result<i32, _>>(), Err(())); } #[test] fn test_iterator_product_option() { let v: &[Option<i32>] = &[Some(1), Some(2), Some(3), Some(4)]; assert_eq!(v.iter().cloned().product::<Option<i32>>(), Some(24)); let v: &[Option<i32>] = &[Some(1), None, Some(3), Some(4)]; assert_eq!(v.iter().cloned().product::<Option<i32>>(), None); }