oxc_coverage_instrument 0.4.1

Istanbul-compatible JavaScript/TypeScript coverage instrumentation using the Oxc AST
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

//! Integration tests for the `source_maps::remap_coverage` API.
//!
//! Covers the Vitest istanbul-reporter path: instrument code that came from an
//! upstream transform (e.g. TypeScript), then walk the resulting `FileCoverage`
//! through its embedded `inputSourceMap` so coverage positions point back at
//! the original source the developer wrote.

use std::collections::BTreeMap;

use oxc_coverage_instrument::{
    FileCoverage, InstrumentOptions, instrument, parse_coverage_map, remap_coverage,
    remap_coverage_map,
};

/// Three-line TypeScript file post type-strip, with an identity-line source map.
/// Each line of intermediate JS maps back to the same line of original TS.
fn three_line_inputs() -> (String, String, String) {
    let original_ts = "const x: number = 1;\nconst y: number = 2;\nconst z: number = 3;\n";
    let intermediate_js = "const x = 1;\nconst y = 2;\nconst z = 3;\n";
    let input_sm = format!(
        r#"{{"version":3,"sources":["src/app.ts"],"sourcesContent":[{original_ts:?}],"mappings":"AAAA;AACA;AACA","names":[]}}"#,
    );
    (original_ts.to_string(), intermediate_js.to_string(), input_sm)
}

#[test]
fn remap_coverage_rewrites_path_to_original_source() {
    let (_, intermediate, input_sm) = three_line_inputs();
    let opts =
        InstrumentOptions { input_source_map: Some(input_sm), ..InstrumentOptions::default() };
    let result = instrument(&intermediate, "intermediate.js", &opts).unwrap();

    let remapped = remap_coverage(&result.coverage_map)
        .expect("remap returns Some when inputSourceMap present");

    assert_eq!(remapped.path, "src/app.ts");
    assert!(
        remapped.input_source_map.is_none(),
        "remapped coverage clears the consumed inputSourceMap"
    );
}

#[test]
fn remap_coverage_resolves_statement_positions_to_original_lines() {
    let (_, intermediate, input_sm) = three_line_inputs();
    let opts =
        InstrumentOptions { input_source_map: Some(input_sm), ..InstrumentOptions::default() };
    let result = instrument(&intermediate, "intermediate.js", &opts).unwrap();

    let remapped = remap_coverage(&result.coverage_map).expect("remap succeeds");

    // Each line of the intermediate JS holds one statement, and the input map
    // is an identity-line mapping back to src/app.ts. Statement lines on the
    // remapped output must therefore be 1, 2, 3 in some order.
    let mut lines: Vec<u32> = remapped.statement_map.values().map(|loc| loc.start.line).collect();
    lines.sort_unstable();
    assert_eq!(lines, vec![1, 2, 3], "statementMap lines after remap, got: {lines:?}");
}

#[test]
fn remap_coverage_applies_source_root() {
    // Input map declares a sourceRoot; the resolved path must join sourceRoot
    // with the first source entry. Matches `istanbul-lib-source-maps`.
    let input_sm = r#"{"version":3,"sourceRoot":"project/","sources":["src/app.ts"],"mappings":"AAAA","names":[]}"#;
    let opts = InstrumentOptions {
        input_source_map: Some(input_sm.to_string()),
        ..InstrumentOptions::default()
    };
    let result = instrument("const x = 1;", "intermediate.js", &opts).unwrap();
    let remapped = remap_coverage(&result.coverage_map).expect("remap succeeds");
    assert_eq!(remapped.path, "project/src/app.ts");
}

#[test]
fn remap_coverage_applies_source_root_without_trailing_slash() {
    // `istanbul-lib-source-maps` inserts a `/` when sourceRoot has none.
    let input_sm = r#"{"version":3,"sourceRoot":"project","sources":["src/app.ts"],"mappings":"AAAA","names":[]}"#;
    let opts = InstrumentOptions {
        input_source_map: Some(input_sm.to_string()),
        ..InstrumentOptions::default()
    };
    let result = instrument("const x = 1;", "intermediate.js", &opts).unwrap();
    let remapped = remap_coverage(&result.coverage_map).expect("remap succeeds");
    assert_eq!(remapped.path, "project/src/app.ts");
}

#[test]
fn remap_coverage_returns_none_without_input_source_map() {
    let result = instrument("const x = 1;", "test.js", &InstrumentOptions::default()).unwrap();
    assert!(
        remap_coverage(&result.coverage_map).is_none(),
        "remap returns None when no inputSourceMap is attached"
    );
}

#[test]
fn remap_coverage_returns_none_when_input_sources_empty() {
    // Source map with empty sources array is unusable for remapping; the
    // function must back off rather than emit a FileCoverage with an empty path.
    let input_sm = r#"{"version":3,"sources":[],"mappings":"","names":[]}"#;
    let opts = InstrumentOptions {
        input_source_map: Some(input_sm.to_string()),
        ..InstrumentOptions::default()
    };
    let result = instrument("const x = 1;", "test.js", &opts).unwrap();
    assert!(remap_coverage(&result.coverage_map).is_none());
}

#[test]
fn remap_coverage_map_rewrites_keys_to_original_paths() {
    let (_, intermediate, input_sm) = three_line_inputs();
    let opts =
        InstrumentOptions { input_source_map: Some(input_sm), ..InstrumentOptions::default() };
    let result = instrument(&intermediate, "intermediate.js", &opts).unwrap();

    let mut coverage: BTreeMap<String, FileCoverage> = BTreeMap::new();
    coverage.insert("intermediate.js".to_string(), result.coverage_map);

    let remapped = remap_coverage_map(&coverage);

    assert!(
        remapped.contains_key("src/app.ts"),
        "remapped coverage map should be keyed by the resolved original path"
    );
    assert!(
        !remapped.contains_key("intermediate.js"),
        "remapped coverage map should not retain the intermediate path"
    );
}

#[test]
fn remap_coverage_map_passes_through_entries_without_input_map() {
    let result = instrument("const x = 1;", "plain.js", &InstrumentOptions::default()).unwrap();
    let mut coverage: BTreeMap<String, FileCoverage> = BTreeMap::new();
    coverage.insert("plain.js".to_string(), result.coverage_map);

    let remapped = remap_coverage_map(&coverage);

    assert!(remapped.contains_key("plain.js"), "passthrough preserves the key");
}

#[test]
fn remap_coverage_round_trips_through_parse_coverage_map() {
    // Simulate the wire shape: serialize to coverage-final.json, parse back,
    // remap. This is the path Vitest's istanbul reporter actually exercises.
    let (_, intermediate, input_sm) = three_line_inputs();
    let opts =
        InstrumentOptions { input_source_map: Some(input_sm), ..InstrumentOptions::default() };
    let result = instrument(&intermediate, "intermediate.js", &opts).unwrap();
    let original_statement_count = result.coverage_map.statement_map.len();

    let coverage_json = format!(
        r#"{{"intermediate.js":{}}}"#,
        serde_json::to_string(&result.coverage_map).unwrap()
    );
    let parsed = parse_coverage_map(&coverage_json).expect("parse coverage-final.json shape");

    let remapped = remap_coverage_map(&parsed);
    let fc = remapped.get("src/app.ts").expect("remapped under original path");
    assert_eq!(
        fc.statement_map.len(),
        original_statement_count,
        "statementMap entries must survive serialize-parse-remap"
    );
    assert_eq!(fc.s.len(), original_statement_count, "hit-count slots must survive the round-trip");
    assert!(fc.input_source_map.is_none(), "inputSourceMap should be consumed during remap");
}