vendor/syn-2.0.8/tests/test_iterators.rs

   1 #![allow(clippy::uninlined_format_args)]
   2
   3 use syn::punctuated::{Pair, Punctuated};
   4 use syn::Token;
   5
   6 #[macro_use]
   7 mod macros;
   8
   9 macro_rules! check_exact_size_iterator {
  10     ($iter:expr) => {{
  11         let iter = $iter;
  12         let size_hint = iter.size_hint();
  13         let len = iter.len();
  14         let count = iter.count();
  15         assert_eq!(len, count);
  16         assert_eq!(size_hint, (count, Some(count)));
  17     }};
  18 }
  19
  20 #[test]
  21 fn pairs() {
  22     let mut p: Punctuated<_, Token![,]> = punctuated!(2, 3, 4);
  23
  24     check_exact_size_iterator!(p.pairs());
  25     check_exact_size_iterator!(p.pairs_mut());
  26     check_exact_size_iterator!(p.into_pairs());
  27
  28     let mut p: Punctuated<_, Token![,]> = punctuated!(2, 3, 4);
  29
  30     assert_eq!(p.pairs().next_back().map(Pair::into_value), Some(&4));
  31     assert_eq!(
  32         p.pairs_mut().next_back().map(Pair::into_value),
  33         Some(&mut 4)
  34     );
  35     assert_eq!(p.into_pairs().next_back().map(Pair::into_value), Some(4));
  36 }
  37
  38 #[test]
  39 fn iter() {
  40     let mut p: Punctuated<_, Token![,]> = punctuated!(2, 3, 4);
  41
  42     check_exact_size_iterator!(p.iter());
  43     check_exact_size_iterator!(p.iter_mut());
  44     check_exact_size_iterator!(p.into_iter());
  45
  46     let mut p: Punctuated<_, Token![,]> = punctuated!(2, 3, 4);
  47
  48     assert_eq!(p.iter().next_back(), Some(&4));
  49     assert_eq!(p.iter_mut().next_back(), Some(&mut 4));
  50     assert_eq!(p.into_iter().next_back(), Some(4));
  51 }
  52
  53 #[test]
  54 fn may_dangle() {
  55     let p: Punctuated<_, Token![,]> = punctuated!(2, 3, 4);
  56     for element in &p {
  57         if *element == 2 {
  58             drop(p);
  59             break;
  60         }
  61     }
  62
  63     let mut p: Punctuated<_, Token![,]> = punctuated!(2, 3, 4);
  64     for element in &mut p {
  65         if *element == 2 {
  66             drop(p);
  67             break;
  68         }
  69     }
  70 }