Testing

What it does

When your agent uses it

• Reviewing tests
• Goldens included
• That use package:test
• Package:fluttertest

Example prompts

• “Dart code only”
• “/testing”

Requirements

• Pre-approved tools (allowed-tools): Read, Glob, Grep, mcp__very-good-cli__test

What it can do on your machine

Read from SKILL.md and the folder at commit 496a3c6. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves these tools, so the agent can use them without asking each time:

  • Read
  • Glob
  • Grep
  • mcp__very-good-cli__test

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Shell commands in SKILL.md call:

  • flutter
  • dart

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Testing loads about 3.2k tokens when it runs, and up to ~10k if it reads all its reference files. Until then it costs about 228 tokens; SKILL.md has 946 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~228

When it runs · the whole SKILL.md, loaded when a task matches

~3.2k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~10k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from VeryGoodOpenSource/vgv-ai-flutter-plugin at commit 496a3c6, republished under its MIT licence (© VeryGoodOpenSource). 946 words, ~3,152 tokens.

name

testing

description

Best practices for Dart unit tests, Flutter widget tests, and golden file tests, covering group and test naming, setUp lifecycle and isolation, mocking with package:mocktail, and the shared pumpApp helper. Use when writing, modifying, or reviewing tests, goldens included, that use package:test, package:flutter_test, package:mocktail, or package:bloc_test, and when no package is named: adding a golden test, matchesGoldenFile, tagging or updating goldens, writing a unit or widget test, or adding a test helper or mock. A one-line golden or widget test request is in scope, including under "Dart code only"; a widget in a UI package is ui-package's. Use it too when the request asks for what these standards forbid: package:mockito, a raw string test tag instead of TestTag, an inline pumpWidget(MaterialApp(...)), asserting padding, color or font size in a widget test, or state shared between tests.

allowed-tools

Read, Glob, Grep, mcp__very-good-cli__test

argument-hint

file-or-directory

class _MockApiClient extends Mock implements ApiClient {}

void main() {
  group(UserRepository, () {
    late ApiClient apiClient;
    late UserRepository subject;

    setUp(() {
      apiClient = _MockApiClient();
      subject = UserRepository(apiClient: apiClient);
    });

    group('getUser', () {
      test('returns $User when API call succeeds', () async {
        when(() => apiClient.fetchUser(any()))
            .thenAnswer((_) async => User(id: '1', name: 'Dash'));

        final result = await subject.getUser('1');

        expect(result, equals(User(id: '1', name: 'Dash')));
        verify(() => apiClient.fetchUser('1')).called(1);
      });

      test('throws $UserNotFoundException when API returns 404', () {
        when(() => apiClient.fetchUser(any()))
            .thenThrow(ApiException(statusCode: 404));

        expect(
          () => subject.getUser('1'),
          throwsA(isA<UserNotFoundException>()),
        );
      });
    });
  });
}

// If _normalizeEmail is private, test it through the public createUser method:
test('normalizes email to lowercase before saving', () async {
  when(() => repository.save(any())).thenAnswer((_) async {});

  await subject.createUser(email: 'Dash@Example.COM');

  final captured = verify(() => repository.save(captureAny())).captured;
  expect(captured.first.email, equals('dash@example.com'));
});

// test/helpers/pump_app.dart
extension PumpApp on WidgetTester {
  Future<void> pumpApp(Widget widget) {
    return pumpWidget(
      MaterialApp(
        home: widget,
      ),
    );
  }
}

import '../helpers/helpers.dart';

void main() {
  group(MyWidget, () {
    testWidgets('renders greeting text', (tester) async {
      await tester.pumpApp(const MyWidget());

      expect(find.text('Hello'), findsOneWidget);
    });
  });
}

© VeryGoodOpenSource, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 9 other files (references) in skills/testing of VeryGoodOpenSource/vgv-ai-flutter-plugin.

• SKILL.md
• agents/openai.yaml
• references/animation-testing.md
• references/configuration.md
• references/coverage.md
• references/golden-tests.md
• references/matchers.md
• references/mocktail.md
• references/test-patterns.md
• references/widget-tests.md

Open the folder on GitHubat commit 496a3c6