group, setUp, and tearDown
Organize tests and share fixtures.
group, setUp, and tearDown is a free Dart Academy lesson on CoddyKit — lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Dart Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Tests Multiply Fast
One feature soon needs many tests. Without structure, a file becomes a flat, hard-to-scan list. Organization keeps it readable. 📚
Meet group
A group bundles related tests under one label. Its output is indented, so suites read like an outline.
group('Cart', () {
test('starts empty', () { /* ... */ });
});Nesting Groups
Groups can nest. The runner joins names with a space, so a failure reads like Cart adds item for instant context.
Repeated Setup Is Noise
If every test rebuilds the same object, that boilerplate hides intent. Shared setup belongs in one place.
Meet setUp
A setUp callback runs before each test in its scope, giving every test a fresh, identical starting state.
late Cart cart;
setUp(() {
cart = Cart();
});Fresh State Every Time
Because setUp runs before each test, no test can leak state into the next. Isolation keeps results trustworthy.
Meet tearDown
A tearDown callback runs after each test, perfect for closing files, sockets, or releasing resources.
tearDown(() {
cart.dispose();
});Scope Matters
setUp and tearDown apply to the group they sit in, including nested groups, so place them where they belong.
Run Once Variants
Need setup just once for a whole group? Use setUpAll and tearDownAll for expensive, shareable resources.
setUpAll(() => startServer());
tearDownAll(() => stopServer());Order of Execution
For each test the runner does setUpAll once, then setUp, the test, then tearDown, and finally tearDownAll at the very end.
Keep Setup Honest
Put only shared, side-effect-free preparation in setUp. Test-specific values still belong inside each test for clarity.
Quick Check
When does a setUp callback run?
Recap
You used group to organize, setUp to prepare fresh state, and tearDown to clean up after each test. Tidy suites, trustworthy results. 🧹
Frequently asked questions
Is the “group, setUp, and tearDown” lesson free?
Yes — the full text of “group, setUp, and tearDown” is free to read here on the web, and the Dart Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Dart Academy course, upgrade to CoddyKit PRO.
What will I learn in “group, setUp, and tearDown”?
Organize tests and share fixtures. You practise Dart Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Dart Academy?
No prior experience is required. Dart Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 2 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “group, setUp, and tearDown” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Dart Academy lesson?
Yes. Every Dart Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Your First test and expect
- group, setUp, and tearDown
- Testing async Code and Streams
- Mocks, Fakes, and Coverage