xmlschema 0.0.3

XML Schema (XSD) validation for Rust, with zero unsafe code
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

// SPDX-License-Identifier: MIT OR Apache-2.0
// Copyright (c) 2026 xmlschema. All rights reserved.

//! Reading `.xsd` documents, including the ways they can be wrong.
//!
//! A schema that fails to parse must say why. Silently producing an
//! empty schema is the worst outcome available: every document then
//! validates, and the caller believes it was checked.

use xmlschema::{Content, parse_schema};

fn schema(body: &str) -> String {
    format!(
        r#"<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">{body}</xs:schema>"#
    )
}

#[test]
fn a_minimal_schema_parses() {
    let s =
        parse_schema(&schema(r#"<xs:element name="note" type="xs:string"/>"#))
            .expect("valid schema");
    assert!(s.element("note").is_some());
    assert!(s.element("missing").is_none());
}

#[test]
fn a_target_namespace_is_recorded() {
    let s = parse_schema(
        r#"<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
             targetNamespace="urn:example">
             <xs:element name="a" type="xs:string"/>
           </xs:schema>"#,
    )
    .expect("valid schema");
    assert_eq!(s.target_namespace.as_deref(), Some("urn:example"));
}

#[test]
fn a_schema_without_a_target_namespace_has_none() {
    let s = parse_schema(&schema(r#"<xs:element name="a" type="xs:string"/>"#))
        .expect("valid schema");
    assert_eq!(s.target_namespace, None);
}

#[test]
fn malformed_xml_is_reported_as_such() {
    let e = parse_schema("<xs:schema><unclosed></xs:schema>")
        .expect_err("not well-formed");
    assert!(e.to_string().contains("well-formed"), "{e}");
}

#[test]
fn an_empty_document_has_no_root_element() {
    let e = parse_schema("").expect_err("no root");
    assert!(!e.to_string().is_empty());
}

#[test]
fn a_non_schema_root_is_rejected() {
    // Pointing at the wrong file is a common mistake, and validating
    // everything against an empty schema would hide it.
    let e = parse_schema("<html><body/></html>").expect_err("not a schema");
    assert!(e.to_string().contains("xs:schema"), "{e}");
}

#[test]
fn a_schema_with_no_top_level_elements_is_rejected() {
    let e = parse_schema(&schema("")).expect_err("nothing declared");
    assert!(e.to_string().contains("top-level"), "{e}");
}

#[test]
fn an_element_without_a_name_is_rejected() {
    let e = parse_schema(&schema(r#"<xs:element type="xs:string"/>"#))
        .expect_err("no name");
    assert!(e.to_string().contains("name"), "{e}");
}

#[test]
fn cardinality_attributes_are_read() {
    let s = parse_schema(&schema(
        r#"<xs:element name="r">
             <xs:complexType><xs:sequence>
               <xs:element name="a" type="xs:string" minOccurs="0"/>
               <xs:element name="b" type="xs:string" maxOccurs="unbounded"/>
               <xs:element name="c" type="xs:string" minOccurs="2" maxOccurs="5"/>
             </xs:sequence></xs:complexType>
           </xs:element>"#,
    ))
    .expect("valid schema");

    let Some(Content::Sequence(parts)) = s.element("r").map(|p| &*p.content)
    else {
        panic!("expected a sequence");
    };
    assert_eq!(parts[0].occurs.min, 0);
    assert_eq!(parts[0].occurs.max, Some(1));
    assert_eq!(parts[1].occurs.max, None, "unbounded");
    assert_eq!(parts[2].occurs.min, 2);
    assert_eq!(parts[2].occurs.max, Some(5));
}

#[test]
fn an_unparseable_cardinality_falls_back_rather_than_failing() {
    // A malformed maxOccurs should not take the whole schema down; the
    // XSD default is the safest reading.
    let s = parse_schema(&schema(
        r#"<xs:element name="r">
             <xs:complexType><xs:sequence>
               <xs:element name="a" type="xs:string" maxOccurs="lots"/>
               <xs:element name="b" type="xs:string" minOccurs="many"/>
             </xs:sequence></xs:complexType>
           </xs:element>"#,
    ))
    .expect("valid schema");
    let Some(Content::Sequence(parts)) = s.element("r").map(|p| &*p.content)
    else {
        panic!("expected a sequence");
    };
    assert_eq!(parts[0].occurs.max, Some(1));
    assert_eq!(parts[1].occurs.min, 1);
}

#[test]
fn xs_all_is_rejected_rather_than_silently_ignored() {
    // Accepting it and validating nothing would be worse than refusing:
    // the caller would believe the constraint was enforced.
    let e = parse_schema(&schema(
        r#"<xs:element name="r">
             <xs:complexType><xs:all>
               <xs:element name="a" type="xs:string"/>
             </xs:all></xs:complexType>
           </xs:element>"#,
    ))
    .expect_err("xs:all is unsupported");
    assert!(e.to_string().to_lowercase().contains("all"), "{e}");
}

#[test]
fn an_element_with_no_type_at_all_is_unconstrained() {
    let s = parse_schema(&schema(r#"<xs:element name="anything"/>"#))
        .expect("valid schema");
    assert!(matches!(
        s.element("anything").map(|p| &*p.content),
        Some(Content::Any)
    ));
}

#[test]
fn a_choice_is_parsed_as_a_choice() {
    let s = parse_schema(&schema(
        r#"<xs:element name="r">
             <xs:complexType><xs:choice>
               <xs:element name="a" type="xs:string"/>
               <xs:element name="b" type="xs:string"/>
             </xs:choice></xs:complexType>
           </xs:element>"#,
    ))
    .expect("valid schema");
    assert!(matches!(
        s.element("r").map(|p| &*p.content),
        Some(Content::Choice(_))
    ));
}

#[test]
fn simple_content_extension_resolves_to_its_base() {
    let s = parse_schema(&schema(
        r#"<xs:element name="priced">
             <xs:complexType><xs:simpleContent>
               <xs:extension base="xs:decimal">
                 <xs:attribute name="currency" type="xs:string"/>
               </xs:extension>
             </xs:simpleContent></xs:complexType>
           </xs:element>"#,
    ))
    .expect("valid schema");
    assert!(matches!(
        s.element("priced").map(|p| &*p.content),
        Some(Content::Simple(_))
    ));
}

#[test]
fn a_named_simple_type_is_resolved_by_reference() {
    let s = parse_schema(&schema(
        r#"<xs:simpleType name="Code">
             <xs:restriction base="xs:string">
               <xs:enumeration value="A"/>
               <xs:enumeration value="B"/>
             </xs:restriction>
           </xs:simpleType>
           <xs:element name="code" type="Code"/>"#,
    ))
    .expect("valid schema");
    let Some(Content::Simple(st)) = s.element("code").map(|p| &*p.content)
    else {
        panic!("expected a simple type");
    };
    assert_eq!(st.facets.enumeration, ["A", "B"]);
}

#[test]
fn attributes_and_their_use_are_read() {
    let s = parse_schema(&schema(
        r#"<xs:element name="r">
             <xs:complexType>
               <xs:sequence/>
               <xs:attribute name="req" type="xs:string" use="required"/>
               <xs:attribute name="opt" type="xs:string"/>
             </xs:complexType>
           </xs:element>"#,
    ))
    .expect("valid schema");
    let attrs = &s.element("r").expect("element").attributes;
    assert_eq!(attrs.len(), 2);
    let req = attrs.iter().find(|a| a.name == "req").expect("req");
    let opt = attrs.iter().find(|a| a.name == "opt").expect("opt");
    assert!(req.required);
    assert!(!opt.required);
}

#[test]
fn the_error_type_displays_its_message() {
    let e = parse_schema("<html/>").expect_err("not a schema");
    assert_eq!(e.to_string(), format!("{e}"));
    assert!(!format!("{e}").is_empty());
}