fluent-iterable 1.0.1

Fluent extension trait for std Iterator, port of @codibre/fluent-iterable vocabulary: joins, grouping, distinctness, cardinality checks
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

// Tests for the cardinality family (spliced into `lib.rs`'s test module).

    #[test]
    fn has_cardinality_matrix() {
        // source length × n → each predicate, matching comparisonRecipe:
        // count(take(n+1)) `op` n
        let len = |n: usize| (0..n).collect::<Vec<_>>();
        assert!(len(2).into_iter().has_exactly(2));
        assert!(!len(3).into_iter().has_exactly(2));
        assert!(!len(1).into_iter().has_exactly(2));
        // count(take(1)) == 0 → empty sequence hasExactly(0), like the JS
        // comparisonRecipe
        assert!(len(0).into_iter().has_exactly(0));
        assert!(len(1).into_iter().has_less_than(2));
        assert!(!len(2).into_iter().has_less_than(2));
        assert!(len(0).into_iter().has_less_than(1));
        assert!(!len(0).into_iter().has_less_than(0));
        assert!(len(2).into_iter().has_less_or_exactly(2));
        assert!(!len(3).into_iter().has_less_or_exactly(2));
        assert!(len(3).into_iter().has_more_than(2));
        assert!(!len(2).into_iter().has_more_than(2));
        assert!(len(2).into_iter().has_more_or_exactly(2));
        assert!(!len(1).into_iter().has_more_or_exactly(2));
        assert!(len(5).into_iter().has_more_or_exactly(2));
    }


    #[test]
    fn has_cardinality_short_circuits() {
        let (source, counter) = counting(0..1_000_000i64);
        assert!(source.has_more_than(2));
        assert_eq!(counter.get(), 3);

        let (source, counter) = counting(0..1_000_000i64);
        assert!(!source.has_less_than(2));
        assert_eq!(counter.get(), 3);

        let (source, counter) = counting(0..1_000_000i64);
        assert!(source.has_more_or_exactly(2));
        assert_eq!(counter.get(), 2);
    }