qubit-budget 0.5.0

Dependency-light resource limit and budget accounting primitives for Qubit Rust crates
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

// =============================================================================
//    Copyright (c) 2025 - 2026 Haixing Hu.
//
//    SPDX-License-Identifier: Apache-2.0
//
//    Licensed under the Apache License, Version 2.0.
// =============================================================================
//! Tests for structural limit configuration.

use qubit_budget::BudgetError;
use qubit_budget::Observation;
use qubit_budget::ResourceLimit;
use qubit_budget::StructureLimits;
use qubit_budget::StructureResource;

#[test]
fn test_has_limits_reports_each_configured_dimension() {
    assert!(!StructureLimits::<StructureResource, usize>::new().has_limits());
    assert!(
        StructureLimits::<StructureResource, usize>::builder()
            .max_depth(1)
            .build()
            .has_limits()
    );
    assert!(
        StructureLimits::<StructureResource, usize>::builder()
            .max_nodes(1)
            .build()
            .has_limits()
    );
    assert!(
        StructureLimits::<StructureResource, usize>::builder()
            .max_sequence_items(1)
            .build()
            .has_limits()
    );
    assert!(
        StructureLimits::<StructureResource, usize>::builder()
            .max_map_entries(1)
            .build()
            .has_limits()
    );
    assert!(
        StructureLimits::<StructureResource, usize>::builder()
            .max_key_bytes(1)
            .build()
            .has_limits()
    );
}

#[test]
fn test_structure_limits_expose_configured_values() {
    let limits = StructureLimits::<StructureResource, usize>::builder()
        .max_depth(1)
        .max_nodes(2)
        .max_sequence_items(3)
        .max_map_entries(4)
        .max_key_bytes(5)
        .build();

    assert_eq!(limits.max_depth(), Some(1));
    assert_eq!(limits.max_nodes(), Some(2));
    assert_eq!(limits.max_sequence_items(), Some(3));
    assert_eq!(limits.max_map_entries(), Some(4));
    assert_eq!(limits.max_key_bytes(), Some(5));
}

/// Verifies custom-resource structural limits use the generic key setter.
#[test]
fn test_generic_structure_limits_support_custom_key_limit() {
    #[derive(Debug, Clone, Copy, PartialEq, Eq)]
    enum Resource {
        KeyBytes,
    }

    let limits = StructureLimits::<Resource, u8>::builder()
        .key_bytes_limit(ResourceLimit::new(Resource::KeyBytes, 3))
        .build();

    assert_eq!(limits.max_key_bytes(), Some(3));
    assert_eq!(limits.key_bytes_limit().unwrap().resource(), &Resource::KeyBytes);
}

#[test]
fn test_builder_max_methods_bind_each_limit_to_its_structure_resource() {
    let mut budget = StructureLimits::<StructureResource, usize>::builder()
        .max_depth(1)
        .max_nodes(1)
        .max_sequence_items(1)
        .max_map_entries(1)
        .build()
        .budget();

    assert!(matches!(
        budget.check_depth(2),
        Err(BudgetError::LimitExceeded {
            resource: StructureResource::Depth,
            observed: Observation::Exact(2),
            maximum: 1,
        })
    ));
    assert!(matches!(budget.charge_node(), Ok(())));
    assert!(matches!(
        budget.charge_node(),
        Err(BudgetError::Insufficient {
            resource: StructureResource::Nodes,
            limit: 1,
            remaining: 0,
            requested: 1,
        })
    ));
    assert!(matches!(
        budget.check_sequence_items(2),
        Err(BudgetError::LimitExceeded {
            resource: StructureResource::SequenceItems,
            observed: Observation::Exact(2),
            maximum: 1,
        })
    ));
    assert!(matches!(
        budget.check_map_entries(2),
        Err(BudgetError::LimitExceeded {
            resource: StructureResource::MapEntries,
            observed: Observation::Exact(2),
            maximum: 1,
        })
    ));
}

#[test]
fn test_to_builder_clones_non_copy_limits_without_consuming_the_original() {
    #[derive(Debug, Clone, PartialEq, Eq)]
    struct OwnedResource(String);

    let depth = OwnedResource("depth".to_owned());
    let nodes = OwnedResource("nodes".to_owned());
    let limits = StructureLimits::<OwnedResource, usize>::builder()
        .depth_limit(ResourceLimit::new(depth.clone(), 2))
        .build();

    let rebuilt = limits
        .to_builder()
        .nodes_limit(ResourceLimit::new(nodes.clone(), 3))
        .build();

    assert_eq!(limits.depth_limit().unwrap().resource(), &depth);
    assert_eq!(limits.max_depth(), Some(2));
    assert_eq!(limits.max_nodes(), None);
    assert_eq!(rebuilt.depth_limit().unwrap().resource(), &depth);
    assert_eq!(rebuilt.nodes_limit().unwrap().resource(), &nodes);
    assert_eq!(rebuilt.max_depth(), Some(2));
    assert_eq!(rebuilt.max_nodes(), Some(3));
}