int-interval 0.8.1

A small, no_std half-open interval algebra library for primitive integer types.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166

// -----------------------------------------------------------------------------
// @generated by xtask/codegen (signed)
// DO NOT EDIT MANUALLY.
// Changes will be overwritten.
// -----------------------------------------------------------------------------

// -----------------------------------------------------------------------------
// @generated by xtask/codegen
// DO NOT EDIT MANUALLY.
// Changes will be overwritten.
// -----------------------------------------------------------------------------

use super::*;

mod unit_tests {
    use super::*;

    fn span(lo: i32, hi: i32) -> I32CO {
        I32CO::try_new(lo, hi).unwrap()
    }

    #[test]
    fn gap_exists() {
        let a = span(1, 3);
        let b = span(6, 8);
        assert_eq!(a.between(b), Some(span(3, 6)));
    }

    #[test]
    fn touching() {
        let a = span(1, 3);
        let b = span(3, 6);
        assert_eq!(a.between(b), None);
    }

    #[test]
    fn overlapping() {
        let a = span(1, 5);
        let b = span(3, 7);
        assert_eq!(a.between(b), None);
    }

    #[test]
    fn contained() {
        let a = span(1, 8);
        let b = span(3, 5);
        assert_eq!(a.between(b), None);
    }

    #[test]
    fn reversed_order_gap_exists() {
        let a = span(6, 8);
        let b = span(1, 3);
        assert_eq!(a.between(b), Some(span(3, 6)));
    }
}

mod prop_tests {
    use std::{vec, vec::Vec};

    use super::*;
    use proptest::prelude::*;

    fn span(a: i32, b: i32) -> Option<I32CO> {
        let lo = a.min(b);
        let hi = a.max(b);
        I32CO::try_new(lo, hi)
    }

    fn edge_values() -> Vec<i32> {
        let mut v = vec![i32::MIN, i32::MAX, 0, 1];

        if i32::MIN < i32::MAX {
            v.push(i32::MIN.saturating_add(1));
            v.push(i32::MAX.saturating_sub(1));
        }

        v.sort_unstable();
        v.dedup();
        v
    }

    fn edge_scalar() -> impl Strategy<Value = i32> {
        prop::sample::select(edge_values())
    }

    fn mixed_scalar() -> impl Strategy<Value = i32> {
        prop_oneof! {
            3 => edge_scalar(),
            7 => any::<i32>(),
        }
    }

    fn span_strategy() -> impl Strategy<Value = I32CO> {
        (mixed_scalar(), mixed_scalar())
            .prop_filter_map("non-empty half-open interval", |(a, b)| span(a, b))
    }

    proptest! {
        #[test]
        fn between_not_overlap(
            x in span_strategy(),
            y in span_strategy(),
            p in mixed_scalar(),
        ) {
            let mid = x.between(y);

            if let Some(mid) = mid {
                prop_assert!(!mid.intersects(x));
                prop_assert!(!mid.intersects(y));

                if mid.contains(p) {
                    prop_assert!(!x.contains(p));
                    prop_assert!(!y.contains(p));
                }
            }
        }

        #[test]
        fn between_correct_bounds(
            x in span_strategy(),
            y in span_strategy(),
        ) {
            let (left, right) = if x.start() <= y.start() { (x, y) } else { (y, x) };
            let expected = I32CO::try_new(left.end_excl(), right.start());

            prop_assert_eq!(x.between(y), expected);
        }

        #[test]
        fn between_symmetric(
            x in span_strategy(),
            y in span_strategy(),
        ) {
            prop_assert_eq!(x.between(y), y.between(x));
        }

        #[test]
        fn between_is_gap_of_hull_minus_union_when_present(
            x in span_strategy(),
            y in span_strategy(),
            p in mixed_scalar(),
        ) {
            if let Some(mid) = x.between(y) {
                let hull = x.convex_hull(y);

                if mid.contains(p) {
                    prop_assert!(hull.contains(p));
                    prop_assert!(!x.contains(p));
                    prop_assert!(!y.contains(p));
                }
            }
        }

        #[test]
        fn between_exists_iff_disjoint_and_not_adjacent(
            x in span_strategy(),
            y in span_strategy(),
        ) {
            prop_assert_eq!(
                x.between(y).is_some(),
                !x.intersects(y) && !x.is_adjacent(y),
            );
        }
    }
}