vr-jcs 0.2.1

RFC 8785 JSON Canonicalization Scheme (JCS) for deterministic serialization in Rust
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
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250

//! RFC 8785 conformance tests driven by test vectors.

#[test]
fn utf16_property_sorting() -> Result<(), vr_jcs::JcsError> {
    let input = serde_json::json!({
        "\u{20ac}": "Euro",
        "\r": "CR",
        "1": "One",
        "\u{0080}": "Ctrl"
    });
    let canon = vr_jcs::to_canon_string(&input)?;
    let expected = "{\"\\r\":\"CR\",\"1\":\"One\",\"\u{0080}\":\"Ctrl\",\"\u{20ac}\":\"Euro\"}";
    assert_eq!(canon, expected);
    Ok(())
}

#[test]
fn empty_structures() -> Result<(), vr_jcs::JcsError> {
    let input = serde_json::json!({"obj": {}, "arr": []});
    let canon = vr_jcs::to_canon_string(&input)?;
    assert_eq!(canon, "{\"arr\":[],\"obj\":{}}");
    Ok(())
}

#[test]
fn nested_sorting() -> Result<(), vr_jcs::JcsError> {
    let input = serde_json::json!({"z": {"z": 1, "a": 2}, "a": 3});
    let canon = vr_jcs::to_canon_string(&input)?;
    assert_eq!(canon, "{\"a\":3,\"z\":{\"a\":2,\"z\":1}}");
    Ok(())
}

#[test]
fn literals() -> Result<(), vr_jcs::JcsError> {
    let input = serde_json::json!([null, true, false]);
    let canon = vr_jcs::to_canon_string(&input)?;
    assert_eq!(canon, "[null,true,false]");
    Ok(())
}

#[test]
fn integer_rendering() -> Result<(), vr_jcs::JcsError> {
    let input = serde_json::json!([0, 1, -1, 42]);
    let canon = vr_jcs::to_canon_string(&input)?;
    assert_eq!(canon, "[0,1,-1,42]");
    Ok(())
}

#[test]
fn negative_zero_renders_as_zero() -> Result<(), vr_jcs::JcsError> {
    let canon = vr_jcs::to_canon_string(&serde_json::json!([-0.0]))?;
    assert_eq!(canon, "[0]");
    Ok(())
}

// ── Rejection vectors ──────────────────────────────────────────────

#[test]
fn reject_duplicate_keys() {
    let result = vr_jcs::to_canon_bytes_from_slice(br#"{"a": 1, "a": 2}"#);
    assert!(result.is_err());
    assert!(result
        .err()
        .is_some_and(|e| e.to_string().contains("duplicate property name")));
}

#[test]
fn reject_nested_duplicate_keys() {
    let result = vr_jcs::to_canon_bytes_from_slice(br#"{"outer": {"a": 1, "a": 2}}"#);
    assert!(result.is_err());
    assert!(result
        .err()
        .is_some_and(|e| e.to_string().contains("duplicate property name")));
}

#[test]
fn reject_noncharacter_u_fdd0() {
    let result = vr_jcs::to_canon_string_from_str("{\"bad\":\"\u{fdd0}\"}");
    assert!(result.is_err());
    assert!(result
        .err()
        .is_some_and(|e| e.to_string().contains("forbidden noncharacter")));
}

// ── RFC 8785 §3.2.6 Number Serialization Test Vectors ─────────────

/// RFC 8785 requires ECMAScript-style number rendering.
/// These are the normative examples from the specification.
#[test]
fn rfc8785_number_zero() -> Result<(), vr_jcs::JcsError> {
    assert_eq!(vr_jcs::to_canon_string(&serde_json::json!(0))?, "0");
    assert_eq!(vr_jcs::to_canon_string(&serde_json::json!(0.0))?, "0");
    assert_eq!(vr_jcs::to_canon_string(&serde_json::json!(-0.0))?, "0");
    Ok(())
}

#[test]
fn rfc8785_number_integers() -> Result<(), vr_jcs::JcsError> {
    assert_eq!(vr_jcs::to_canon_string(&serde_json::json!(1))?, "1");
    assert_eq!(vr_jcs::to_canon_string(&serde_json::json!(-1))?, "-1");
    assert_eq!(vr_jcs::to_canon_string(&serde_json::json!(42))?, "42");
    assert_eq!(
        vr_jcs::to_canon_string(&serde_json::json!(999_999_999_999_i64))?,
        "999999999999"
    );
    Ok(())
}

#[test]
fn rfc8785_number_fractions() -> Result<(), vr_jcs::JcsError> {
    assert_eq!(vr_jcs::to_canon_string(&serde_json::json!(0.5))?, "0.5");
    assert_eq!(vr_jcs::to_canon_string(&serde_json::json!(-0.5))?, "-0.5");
    assert_eq!(vr_jcs::to_canon_string(&serde_json::json!(1.5))?, "1.5");
    assert_eq!(vr_jcs::to_canon_string(&serde_json::json!(0.1))?, "0.1");
    Ok(())
}

/// RFC 8785 §3.2.6: "If there are multiple such representations...
/// the representation with the fewest significant digits is chosen."
#[test]
fn rfc8785_shortest_representation() -> Result<(), vr_jcs::JcsError> {
    // 1e20 should render as 100000000000000000000, not 1e+20
    assert_eq!(
        vr_jcs::to_canon_string(&serde_json::json!(1e20))?,
        "100000000000000000000"
    );
    // 1e21 should use exponential: 1e+21
    assert_eq!(vr_jcs::to_canon_string(&serde_json::json!(1e21))?, "1e+21");
    Ok(())
}

#[test]
fn rfc8785_exponential_notation() -> Result<(), vr_jcs::JcsError> {
    assert_eq!(
        vr_jcs::to_canon_string(&serde_json::json!(1e100))?,
        "1e+100"
    );
    assert_eq!(vr_jcs::to_canon_string(&serde_json::json!(1e-7))?, "1e-7");
    assert_eq!(
        vr_jcs::to_canon_string(&serde_json::json!(2.220_446_049_250_313e-16))?,
        "2.220446049250313e-16"
    );
    Ok(())
}

// ── RFC 8785 §3.2.3 String Serialization ──────────────────────────

#[test]
fn rfc8785_string_escaping() -> Result<(), vr_jcs::JcsError> {
    // Control characters 0x00-0x1F must be escaped
    let input = serde_json::json!({"tab": "\t", "newline": "\n", "cr": "\r"});
    let canon = vr_jcs::to_canon_string(&input)?;
    assert!(canon.contains("\\t"), "tab must be escaped: {canon}");
    assert!(canon.contains("\\n"), "newline must be escaped: {canon}");
    assert!(canon.contains("\\r"), "cr must be escaped: {canon}");
    Ok(())
}

#[test]
fn rfc8785_backslash_and_quote_escaping() -> Result<(), vr_jcs::JcsError> {
    let input = serde_json::json!({"bs": "a\\b", "qt": "a\"b"});
    let canon = vr_jcs::to_canon_string(&input)?;
    assert!(
        canon.contains("a\\\\b"),
        "backslash must be escaped: {canon}"
    );
    assert!(canon.contains("a\\\"b"), "quote must be escaped: {canon}");
    Ok(())
}

// ── RFC 8785 §3.2.4 Property Ordering ─────────────────────────────

/// RFC 8785 requires sorting by UTF-16 code units, not UTF-8 bytes.
#[test]
fn rfc8785_property_ordering_ascii() -> Result<(), vr_jcs::JcsError> {
    let canon = vr_jcs::to_canon_string(&serde_json::json!({"z": 1, "a": 2}))?;
    assert_eq!(canon, r#"{"a":2,"z":1}"#);
    Ok(())
}

#[test]
fn rfc8785_property_ordering_unicode() -> Result<(), vr_jcs::JcsError> {
    // RFC 8785 §3.2.4 example: properties sorted by UTF-16 code unit values
    let input = serde_json::json!({
        "\u{20ac}": "Euro Sign",
        "\r": "Carriage Return",
        "\u{000a}": "Newline",
        "1": "One"
    });
    let canon = vr_jcs::to_canon_string(&input)?;
    // Expected order by UTF-16 code units: \n (000A), \r (000D), "1" (0031), € (20AC)
    assert!(
        canon.find("Newline") < canon.find("Carriage Return"),
        "\\n before \\r: {canon}"
    );
    assert!(
        canon.find("Carriage Return") < canon.find("One"),
        "\\r before 1: {canon}"
    );
    assert!(
        canon.find("One") < canon.find("Euro Sign"),
        "1 before €: {canon}"
    );
    Ok(())
}

// ── RFC 8785 §3.2.5 Duplicate Property Rejection ─────────────────

#[test]
fn rfc8785_duplicate_rejection() {
    // RFC 8785 §3.2.5: "If an object contains a duplicate property
    // name, this MUST be treated as an error."
    let result = vr_jcs::to_canon_bytes_from_slice(br#"{"dup": 1, "dup": 2}"#);
    assert!(result.is_err());
}

// ── RFC 8785 §3.2.2 Literal Serialization ─────────────────────────

#[test]
fn rfc8785_literals() -> Result<(), vr_jcs::JcsError> {
    assert_eq!(vr_jcs::to_canon_string(&serde_json::json!(null))?, "null");
    assert_eq!(vr_jcs::to_canon_string(&serde_json::json!(true))?, "true");
    assert_eq!(vr_jcs::to_canon_string(&serde_json::json!(false))?, "false");
    Ok(())
}

// ── Composite: RFC 8785 §3.2.7 Full Example ───────────────────────

#[test]
#[allow(clippy::excessive_precision)]
fn rfc8785_composite_example() -> Result<(), vr_jcs::JcsError> {
    let input = serde_json::json!({
        "numbers": [333_333_333.333_333_29, 1e30, 4.50, 2e-3, 0.000_000_000_000_000_000_000_000_001],
        "string": "\u{20ac}$\u{000f}\u{000a}A'\u{0042}\\\\\"/",
        "literals": [null, true, false]
    });
    let canon = vr_jcs::to_canon_string(&input)?;
    // Verify it parses back
    let _: serde_json::Value = serde_json::from_str(&canon).map_err(vr_jcs::JcsError::from)?;
    // Verify keys are sorted
    assert!(
        canon.find("\"literals\"") < canon.find("\"numbers\""),
        "literals before numbers: {canon}"
    );
    assert!(
        canon.find("\"numbers\"") < canon.find("\"string\""),
        "numbers before string: {canon}"
    );
    Ok(())
}