dart-collect-coverage

What the source does

• FilesystemNone observedNo reads or writes in the source
• NetworkNone observedNo outbound calls in the source
• ShellNone observedNo commands run in the source
• DependenciesPinnedNothing floats
• SecretsNone foundNo keys in source

Five audit layers

Gates applied: no behavioural pass.

dart run coverage:collect_coverage --wait-paused --uri=http://127.0.0.1:8181/ -o coverage/coverage.json --resume-isolates

Audit 0.4.1 · source sha db37821a6b02 · 22 Oct 2026Report an issue or request a re-scan

• Publisherdart-lang GitHub organizationOwner of the repository this skill is read from
• Source folderdart-lang/skills/skills/dart-collect-coverageThe exact folder we audited
• LicenceBSD-3-ClauseAs the repository states it
• Commit pinned for this verdictdb37821a6b02A new audit runs when the source changes
• Repository statusNot archivedLast push 5 days ago
• Sandboxed runNot runSkills are read, not executed; layer L4 is skipped

Its description: Collect coverage using the coverage packge and create an LCOV report

---
name: dart-collect-coverage
description: Collect coverage using the coverage packge and create an LCOV report
metadata:
  model: models/gemini-3.1-pro-preview
  last_modified: Fri, 24 Apr 2026 15:14:32 GMT
---
# Implementing Dart and Flutter Test Coverage

## Contents
- [Testing Fundamentals](#testing-fundamentals)
- [Coverage Directives](#coverage-directives)
- [Workflow: Configuring and Generating Coverage Reports](#workflow-configuring-and-generating-coverage-reports)
- [Workflow: Advanced Manual Coverage Collection](#workflow-advanced-manual-coverage-collection)
- [Examples](#examples)

## Testing Fundamentals

Structure your test suites using the standard Dart testing paradigms. Use `package:test` for Dart projects and `flutter_test` for Flutter projects.

- **Unit Tests:** Verify individual functions, methods, or classes.
- **Component/Widget Tests:** Verify component behavior, layout, and interaction using mock objects (`package:mockito`).
- **Integration Tests:** Verify entire app flows on simulated or real devices.

## Coverage Directives

Exclude specific lines, blocks, or entire files from coverage metrics using inline comments. Pass the `--check-ignore` flag during formatting to enforce these directives.

- Ignore a single line: `// coverage:ignore-line`
- Ignore a block of code: `// coverage:ignore-start` and `// coverage:ignore-end`
- Ignore an entire file: `// coverage:ignore-file`

## Workflow: Configuring and Generating Coverage Reports

Follow this sequential workflow to add the coverage package, execute tests, and generate an LCOV report.

**Task Progress Checklist:**
- [ ] 1. Add `coverage` as a `dev_dependency`.
- [ ] 2. Execute the automated coverage script.
- [ ] 3. Validate the LCOV output.

### 1. Add Dependencies
Add the `coverage` package as a `dev_dependency` to your project. Do not add it to standard dependencies.

If working in a standard Dart project:
```bash
dart pub add dev:coverage
```

If working in a Flutter project:
```bash
flutter pub add dev:coverage
```

### 2. Collect Coverage and Generate LCOV
Use the bundled `test_with_coverage` script. This script automatically runs all tests, collects the JSON coverage data from the Dart VM, and formats it into an LCOV report.

```bash
dart run coverage:test_with_coverage
```
*Note: If working within a Dart workspace (monorepo), specify the test directories explicitly (e.g., `dart run coverage:test_with_coverage -- pkgs/foo/test pkgs/bar/test`).*

### 3. Feedback Loop: Validate Output
**Run validator -> review errors -> fix:**
1. Verify that the `coverage/` directory was created in the project root.
2. Ensure `coverage/coverage.json` (raw data) and `coverage/lcov.info` (formatted report) exist.
3. If coverage is missing for specific files, ensure they are imported and executed by your test files, or add `// coverage:ignore-file` if they are intentionally excluded.

## Workflow: Advanced Manual Coverage Collection

If you require granular control over the VM service, isolate pausing, or need branch/function-level coverage, use the manual collection workflow.

**Task Progress Checklist:**
- [ ] 1. Run tests with VM service enabled.
- [ ] 2. Collect raw JSON coverage.
- [ ] 3. Format JSON to LCOV.

### 1. Run Tests with VM Service
Execute tests while pausing isolates on exit and exposing the VM service on a specific port (e.g., 8181).

```bash
dart run --pause-isolates-on-exit --disable-service-auth-codes --enable-vm-service=8181 test &
```

### 2. Collect Raw Coverage
Extract the coverage data from the running VM service and output it to a JSON file.

```bash
dart run coverage:collect_coverage --wait-paused --uri=http://127.0.0.1:8181/ -o coverage/coverage.json --resume-isolates
```
*Optional: Append `--function-coverage` and `--branch-coverage` to gather deeper metrics (requires Dart VM 2.17.0+).*

### 3. Format to LCOV
Convert the raw JSON data into the standard LCOV format.

```bash
dart run coverage:format_coverage --packages=.dart_tool/package_config.json --lcov -i coverage/coverage.json -o coverage/lcov.info --check-ignore
```

## Examples

### Example: `pubspec.yaml` Configuration
Ensure your `pubspec.yaml` reflects the `coverage` package strictly under `dev_dependencies`.

```yaml
name: my_dart_app
environment:
  sdk: ^3.0.0

dependencies:
  path: ^1.8.0

dev_dependencies:
  test: ^1.24.0
  coverage: ^1.15.0
```

### Example: Applying Ignore Directives
Use ignore directives to prevent generated code or untestable edge cases from lowering coverage scores.

```dart
// coverage:ignore-file
import 'package:meta/meta.dart';

class SystemConfig {
  final String env;

  SystemConfig(this.env);

  // coverage:ignore-start
  void legacyInit() {
    print('Deprecated initialization');
  }
  // coverage:ignore-end

  bool isProduction() {
    if (env == 'prod') return true;
    return false; // coverage:ignore-line
  }
}
```

Excerpt, first 4,892 characters of SKILL.md, verbatim from the audited commit. It is text from someone else’s repository, quoted so you can judge it before your agent reads it.

git clone https://github.com/dart-lang/skills
git -C skills checkout db37821a6b02

Works in

1. 2026-10-22
   ✓SAFE B 89 / 100

   first audit · source db37821a6b02

Questions about dart-collect-coverage

• github.com/dart-lang/skills/tree/main/skills/dart-collect-covera — the audited source at commit db37821a6b02 and every finding aboveObserved · 22 Oct 2026

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