dart-add-unit-test

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.

Audit 0.4.1 · source sha db37821a6b02 · 20 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-add-unit-testThe 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 3 days ago
• Sandboxed runNot runSkills are read, not executed; layer L4 is skipped

Its description: Write and organize unit tests for functions, methods, and classes using `package:test`. Use when creating new logic or fixing bugs to ensure code remains correct and regression-free.

---
name: dart-add-unit-test
description: Write and organize unit tests for functions, methods, and classes using `package:test`. Use when creating new logic or fixing bugs to ensure code remains correct and regression-free.
metadata:
  model: models/gemini-3.1-pro-preview
  last_modified: Mon, 03 Aug 2026 21:51:24 GMT
---
# Testing Dart and Flutter Applications

## Contents
- [Structuring Test Files](#structuring-test-files)
- [Writing Tests](#writing-tests)
- [Executing Tests](#executing-tests)
- [Test Implementation Workflow](#test-implementation-workflow)
- [Examples](#examples)

## Structuring Test Files
Organize test files to mirror the `lib` directory structure to maintain predictability.

* Place all test code within the `test` directory at the root of the package.
* Append `_test.dart` to the end of all test file names (e.g., `lib/src/utils.dart` should be tested in `test/src/utils_test.dart`).
* If writing integration tests, place them in an `integration_test` directory at the root of the package.

## Writing Tests
Utilize `package:test` as the standard testing library for Dart applications.

* Import `package:test/test.dart` (or `package:flutter_test/flutter_test.dart` for Flutter).
* Group related tests using the `group()` function to provide shared context.
* Define individual test cases using the `test()` function.
* Validate outcomes using the `expect()` function alongside matchers (e.g., `equals()`, `isTrue`, `throwsA()`).
* Write asynchronous tests using standard `async`/`await` syntax. The test runner automatically waits for the `Future` to complete.
* Manage test setup and teardown using `setUp()` and `tearDown()` callbacks.
* If testing code that relies on dependency injection, use `package:mockito` alongside `package:test` to generate mock objects, configure fixed scenarios, and verify interactions.

## Executing Tests
Select the appropriate test runner based on the project type and test location.

* If working on a pure Dart project, execute tests using the `dart test` command.
* If working on a Flutter project, execute tests using the `flutter test` command.
* If running integration tests, explicitly specify the directory path, as the default runner ignores it: `dart test integration_test` or `flutter test integration_test`.

## Test Implementation Workflow

Follow this sequential workflow when implementing new test suites. Copy the checklist to track your progress.

### Task Progress
- [ ] 1. Create the test file in the `test/` directory, ensuring the `_test.dart` suffix.
- [ ] 2. Import `package:test/test.dart` and the target library.
- [ ] 3. Define a `main()` function.
- [ ] 4. Initialize shared resources or mocks using `setUp()`.
- [ ] 5. Write `test()` cases grouped by functionality using `group()`.
- [ ] 6. Execute the test suite using the appropriate CLI command.
- [ ] 7. **Feedback Loop**: Run test -> Review stack trace for failures -> Fix implementation or assertions -> Re-run until passing.

## Examples

### Standard Unit Test Suite
Demonstrates grouping, setup, synchronous, and asynchronous testing.

```dart
import 'package:test/test.dart';
import 'package:my_package/calculator.dart';

void main() {
  group('Calculator', () {
    late Calculator calc;

    setUp(() {
      calc = Calculator();
    });

    test('adds two numbers correctly', () {
      expect(calc.add(2, 3), equals(5));
    });

    test('handles asynchronous operations', () async {
      final result = await calc.fetchRemoteValue();
      expect(result, isNotNull);
      expect(result, greaterThan(0));
    });
  });
}
```

### Mocking with Mockito
Demonstrates configuring a mock object for dependency injection testing.

```dart
import 'package:test/test.dart';
import 'package:mockito/mockito.dart';
import 'package:mockito/annotations.dart';
import 'package:my_package/api_client.dart';
import 'package:my_package/data_service.dart';

// Generate the mock using build_runner: dart run build_runner build
@GenerateNiceMocks([MockSpec<ApiClient>()])
import 'data_service_test.mocks.dart';

void main() {
  group('DataService', () {
    late MockApiClient mockApiClient;
    late DataService dataService;

    setUp(() {
      mockApiClient = MockApiClient();
      dataService = DataService(apiClient: mockApiClient);
    });

    test('returns parsed data on successful API call', () async {
      // Configure the mock
      when(mockApiClient.get('/data')).thenAnswer((_) async => '{"id": 1}');

      // Execute the system under test
      final result = await dataService.fetchData();

      // Verify outcomes and interactions
      expect(result.id, equals(1));
      verify(mockApiClient.get('/data')).called(1);
    });
  });
}
```

Excerpt, first 4,708 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. 2026-10-20
   ✓SAFE B 89 / 100

   first audit · source db37821a6b02

Questions about dart-add-unit-test

• github.com/dart-lang/skills/tree/main/skills/dart-add-unit-test — the audited source at commit db37821a6b02 and every finding aboveObserved · 20 Oct 2026

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