diff-struct 0.3.1

A trait for diffing and apply diffs to structs of a certain type
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

use super::*;

use std::collections::{HashMap, HashSet};
use std::fmt::Debug;
use std::hash::Hash;

fn identity_test<D: Diff + Debug + PartialEq>(s: D) {
    assert_eq!(D::identity().apply_new(&D::identity().diff(&s)), s);
}

fn generate_map<K: Eq + Hash, V>(parts: Vec<(K, V)>) -> HashMap<K, V> {
    parts.into_iter().collect::<HashMap<_, _>>()
}

#[test]
fn numeric_diffs() {
    identity_test(true);
    identity_test(42_u8);
    identity_test(42_i8);
    identity_test(42_u16);
    identity_test(42_i16);
    identity_test(42_u32);
    identity_test(42_i32);
    identity_test(42.0_f32);
    identity_test(42.0_f64);
}

#[test]
fn test_char_string() {
    identity_test('b');
    identity_test(String::from("42"));
    assert_eq!('b'.diff(&'c'), Some('c'));
    assert_eq!('b'.diff(&'b'), None);
    assert_eq!(String::from("42").diff(&String::from("asdf")), Some(String::from("asdf")));
    assert_eq!(String::from("42").diff(&String::from("42")), None);
}

#[test]
fn test_opt() {
    assert_eq!(Some(10).diff(&Some(15)), OptionDiff::Some(5));
    assert_eq!(None.apply_new(&OptionDiff::Some(5)), Some(5));
    assert_eq!(Some(100).apply_new(&OptionDiff::None), None);
    identity_test(Some(42))
}

#[test]
fn test_maps() {
    let a = generate_map(vec![("a", 1), ("b", 2), ("x", 42)]);
    let b = generate_map(vec![("b", 3), ("c", 4), ("x", 42)]);
    let expected = HashMapDiff {
        altered: generate_map(vec![("b", 1), ("c", 4)]),
        removed: vec!["a"].into_iter().collect::<HashSet<_>>(),
    };
    assert_eq!(a.diff(&b), expected);
    identity_test(a);
}

#[derive(Debug, PartialEq, Diff)]
#[diff(attr(
    #[derive(Debug, PartialEq)]
))]
struct TestStruct {
    a: bool,
    b: u32,
}

#[test]
fn test_derive() {
    let a = TestStruct { a: false, b: 42 };

    let b = TestStruct { a: true, b: 43 };

    let diff = TestStructDiff {
        a: true.into(),
        b: 1,
    };
    assert_eq!(a.diff(&b), diff);

    identity_test(a);
}

#[derive(Debug, PartialEq, Diff)]
#[diff(attr(
    #[derive(Debug, PartialEq)]
))]
struct TestTupleStruct(i32);

#[test]
fn test_tuple_derive() {
    let a = TestTupleStruct(10);
    let b = TestTupleStruct(30);
    let diff = TestTupleStructDiff(20);
    assert_eq!(a.diff(&b), diff);
}

#[derive(Debug, Default, PartialEq, Diff)]
pub struct ProjectMeta {
    contributors: Vec<String>,
    combined_work_hours: usize,
}

#[test]
fn test_apply() {
    let mut base = ProjectMeta::default();
    let contribution_a = ProjectMeta {
        contributors: vec!["Alice".into()],
        combined_work_hours: 3,
    };
    let contribution_b = ProjectMeta {
        contributors: vec!["Bob".into(), "Candice".into()],
        combined_work_hours: 10,
    };
    let expected = ProjectMeta {
        contributors: vec!["Bob".into(), "Candice".into(), "Alice".into()],
        combined_work_hours: 13,
    };
    let diff_a = base.diff(&contribution_a);
    let diff_b = base.diff(&contribution_b);
    base.apply(&diff_a);
    base.apply(&diff_b);
    assert_eq!(base, expected);
}

#[test]
fn test_vecs() {
    let a = vec![0, 1, 2, 3, 4, 5, 6, 7];
    let b = vec![0, /*1, 2*/ 3, 4, 42, 5, /*6 ->*/ 10, 7];
    let diff = VecDiff(vec![
        VecDiffType::Removed { index: 1, len: 2 },
        VecDiffType::Inserted {
            index: 5,
            changes: vec![42],
        },
        VecDiffType::Altered {
            index: 6,
            changes: vec![4], // add 4 to 6
        },
    ]);
    assert_eq!(diff, a.diff(&b));
    assert_eq!(a.apply_new(&diff), b);
}