diff options
| -rw-r--r-- | library/alloc/tests/slice.rs | 119 |
1 files changed, 55 insertions, 64 deletions
diff --git a/library/alloc/tests/slice.rs b/library/alloc/tests/slice.rs index fe3d7183ee2..4211cd42b02 100644 --- a/library/alloc/tests/slice.rs +++ b/library/alloc/tests/slice.rs @@ -1,6 +1,7 @@ use std::cell::Cell; use std::cmp::Ordering::{self, Equal, Greater, Less}; use std::convert::identity; +use std::fmt; use std::mem; use std::panic; use std::rc::Rc; @@ -995,75 +996,65 @@ fn test_rsplitnator() { #[test] fn test_split_iterators_size_hint() { - for len in 0..=2 { - let mut v: Vec<u8> = (0..len).collect(); - fn verify_descending(sequence: &[usize], context: &str) { - let len = sequence.len(); - let target: Vec<usize> = (0..len).rev().collect(); - assert_eq!(sequence, target, "while testing: {}", context); - } - - macro_rules! test_size_hint { - ($create_iterator:expr) => {{ - // with a predicate always returning false, the split*-iterators - // become maximally short, so the size_hint lower bounds are correct - - macro_rules! p { - () => { - |_| false - }; - } - let mut short_iterator = $create_iterator; - let mut lower_bounds = vec![short_iterator.size_hint().0]; - while let Some(_) = short_iterator.next() { - lower_bounds.push(short_iterator.size_hint().0); + #[derive(Copy, Clone)] + enum Bounds { + Lower, + Upper, + } + fn assert_precise_size_hints<I: Iterator>( + mut it: I, + which: Bounds, + context: impl fmt::Display, + ) { + match which { + Bounds::Lower => { + let mut lower_bounds = vec![it.size_hint().0]; + while let Some(_) = it.next() { + lower_bounds.push(it.size_hint().0); } - verify_descending(&lower_bounds, stringify!($create_iterator)); + let target: Vec<_> = (0..lower_bounds.len()).rev().collect(); + assert_eq!(lower_bounds, target, "incorrect lower bounds: {}", context); } - { - // with a predicate always returning true, the split*-iterators - // become maximally long, so the size_hint upper bounds are correct - - macro_rules! p { - () => { - |_| true - }; - } - let mut long_iterator = $create_iterator; - let mut upper_bounds = vec![ - long_iterator.size_hint().1.expect("split*-methods have known upper bound"), - ]; - while let Some(_) = long_iterator.next() { - upper_bounds.push( - long_iterator.size_hint().1.expect("split*-methods have known upper bound"), - ); + Bounds::Upper => { + let mut upper_bounds = vec![it.size_hint().1]; + while let Some(_) = it.next() { + upper_bounds.push(it.size_hint().1); } - verify_descending(&upper_bounds, stringify!($create_iterator)); - }}; + let target: Vec<_> = (0..upper_bounds.len()).map(Some).rev().collect(); + assert_eq!(upper_bounds, target, "incorrect upper bounds: {}", context); + } } + } - test_size_hint!(v.split(p!())); - test_size_hint!(v.split_mut(p!())); - test_size_hint!(v.splitn(0, p!())); - test_size_hint!(v.splitn(1, p!())); - test_size_hint!(v.splitn(2, p!())); - test_size_hint!(v.splitn(3, p!())); - test_size_hint!(v.splitn_mut(0, p!())); - test_size_hint!(v.splitn_mut(1, p!())); - test_size_hint!(v.splitn_mut(2, p!())); - test_size_hint!(v.splitn_mut(3, p!())); - test_size_hint!(v.split_inclusive(p!())); - test_size_hint!(v.split_inclusive_mut(p!())); - test_size_hint!(v.rsplit(p!())); - test_size_hint!(v.rsplit_mut(p!())); - test_size_hint!(v.rsplitn(0, p!())); - test_size_hint!(v.rsplitn(1, p!())); - test_size_hint!(v.rsplitn(2, p!())); - test_size_hint!(v.rsplitn(3, p!())); - test_size_hint!(v.rsplitn_mut(0, p!())); - test_size_hint!(v.rsplitn_mut(1, p!())); - test_size_hint!(v.rsplitn_mut(2, p!())); - test_size_hint!(v.rsplitn_mut(3, p!())); + for len in 0..=2 { + let mut v: Vec<u8> = (0..len).collect(); + + // p: predicate, b: bound selection + for (p, b) in [ + // with a predicate always returning false, the split*-iterators + // become maximally short, so the size_hint lower bounds are correct + ((|_| false) as fn(&_) -> _, Bounds::Lower), + // with a predicate always returning true, the split*-iterators + // become maximally long, so the size_hint upper bounds are correct + ((|_| true) as fn(&_) -> _, Bounds::Upper), + ] { + use assert_precise_size_hints as a; + use format_args as f; + + a(v.split(p), b, "split"); + a(v.split_mut(p), b, "split_mut"); + a(v.split_inclusive(p), b, "split_inclusive"); + a(v.split_inclusive_mut(p), b, "split_inclusive_mut"); + a(v.rsplit(p), b, "rsplit"); + a(v.rsplit_mut(p), b, "rsplit_mut"); + + for n in 0..=3 { + a(v.splitn(n, p), b, f!("splitn, n = {}", n)); + a(v.splitn_mut(n, p), b, f!("splitn_mut, n = {}", n)); + a(v.rsplitn(n, p), b, f!("rsplitn, n = {}", n)); + a(v.rsplitn_mut(n, p), b, f!("rsplitn_mut, n = {}", n)); + } + } } } |