1 use super::*;
2
3 #[test]
same_range_first_consumers_return_correct_answer()4 fn same_range_first_consumers_return_correct_answer() {
5 let find_op = |x: &i32| x % 2 == 0;
6 let first_found = AtomicUsize::new(usize::max_value());
7 let far_right_consumer = FindConsumer::new(&find_op, MatchPosition::Leftmost, &first_found);
8
9 // We save a consumer that will be far to the right of the main consumer (and therefore not
10 // sharing an index range with that consumer) for fullness testing
11 let consumer = far_right_consumer.split_off_left();
12
13 // split until we have an indivisible range
14 let bits_in_usize = usize::min_value().count_zeros();
15
16 for _ in 0..bits_in_usize {
17 consumer.split_off_left();
18 }
19
20 let reducer = consumer.to_reducer();
21 // the left and right folders should now have the same range, having
22 // exhausted the resolution of usize
23 let left_folder = consumer.split_off_left().into_folder();
24 let right_folder = consumer.into_folder();
25
26 let left_folder = left_folder.consume(0).consume(1);
27 assert_eq!(left_folder.boundary, right_folder.boundary);
28 // expect not full even though a better match has been found because the
29 // ranges are the same
30 assert!(!right_folder.full());
31 assert!(far_right_consumer.full());
32 let right_folder = right_folder.consume(2).consume(3);
33 assert_eq!(
34 reducer.reduce(left_folder.complete(), right_folder.complete()),
35 Some(0)
36 );
37 }
38
39 #[test]
same_range_last_consumers_return_correct_answer()40 fn same_range_last_consumers_return_correct_answer() {
41 let find_op = |x: &i32| x % 2 == 0;
42 let last_found = AtomicUsize::new(0);
43 let consumer = FindConsumer::new(&find_op, MatchPosition::Rightmost, &last_found);
44
45 // We save a consumer that will be far to the left of the main consumer (and therefore not
46 // sharing an index range with that consumer) for fullness testing
47 let far_left_consumer = consumer.split_off_left();
48
49 // split until we have an indivisible range
50 let bits_in_usize = usize::min_value().count_zeros();
51 for _ in 0..bits_in_usize {
52 consumer.split_off_left();
53 }
54
55 let reducer = consumer.to_reducer();
56 // due to the exact calculation in split_off_left, the very last consumer has a
57 // range of width 2, so we use the second-to-last consumer instead to get
58 // the same boundary on both folders
59 let consumer = consumer.split_off_left();
60 let left_folder = consumer.split_off_left().into_folder();
61 let right_folder = consumer.into_folder();
62 let right_folder = right_folder.consume(2).consume(3);
63 assert_eq!(left_folder.boundary, right_folder.boundary);
64 // expect not full even though a better match has been found because the
65 // ranges are the same
66 assert!(!left_folder.full());
67 assert!(far_left_consumer.full());
68 let left_folder = left_folder.consume(0).consume(1);
69 assert_eq!(
70 reducer.reduce(left_folder.complete(), right_folder.complete()),
71 Some(2)
72 );
73 }
74
75 // These tests requires that a folder be assigned to an iterator with more than
76 // one element. We can't necessarily determine when that will happen for a given
77 // input to find_first/find_last, so we test the folder directly here instead.
78 #[test]
find_first_folder_does_not_clobber_first_found()79 fn find_first_folder_does_not_clobber_first_found() {
80 let best_found = AtomicUsize::new(usize::max_value());
81 let f = FindFolder {
82 find_op: &(|&_: &i32| -> bool { true }),
83 boundary: 0,
84 match_position: MatchPosition::Leftmost,
85 best_found: &best_found,
86 item: None,
87 };
88 let f = f.consume(0_i32).consume(1_i32).consume(2_i32);
89 assert!(f.full());
90 assert_eq!(f.complete(), Some(0_i32));
91 }
92
93 #[test]
find_last_folder_yields_last_match()94 fn find_last_folder_yields_last_match() {
95 let best_found = AtomicUsize::new(0);
96 let f = FindFolder {
97 find_op: &(|&_: &i32| -> bool { true }),
98 boundary: 0,
99 match_position: MatchPosition::Rightmost,
100 best_found: &best_found,
101 item: None,
102 };
103 let f = f.consume(0_i32).consume(1_i32).consume(2_i32);
104 assert_eq!(f.complete(), Some(2_i32));
105 }
106