GWT Testing

Use these instructions to write clean, readable tests with Given/When/Then semantics.

Terminology Map

Use the agnostic terms below throughout this skill.

Agnostic term	JS/TS example	Dart example
Suite block	describe	group
Case block	it / test	test
Setup once (for a suite)	before	setUpAll
Setup each (per case)	beforeEach	setUp
Teardown once (for a suite)	after	tearDownAll
Teardown each (per case)	afterEach	tearDown

When this skill says:

• "suite block", read describe (JS/TS) or group (Dart)
• "case block", read it/test (JS/TS) or test (Dart)
• "setup hook", read before/beforeEach (JS/TS) or setUpAll/setUp (Dart)
• "teardown hook", read after/afterEach (JS/TS) or tearDownAll/tearDown (Dart)

Rules

1. Keep maximum nesting depth to 3 levels: suite -> suite -> case.
2. Never nest Given blocks inside another Given block.
3. Put setup and action code in setup hooks for the scenario.
4. Prefer assertion-only case blocks.
5. If a When has only one Then, use a single case title (When ... then ...); in this collapsed form, putting the When action inside the case body is acceptable.
6. Remove wrapper describes that do not add scenario context.
7. Write explicit scenario titles: Given <subject> with <condition>.

Writing Workflow

1. Define scenarios as top-level Given suite blocks.
2. Add setup hooks per scenario to arrange and act.
3. Add case blocks for outcomes (When ... then ...) with assertions only.
4. Keep nesting shallow and remove redundant wrappers.
5. Run tests and formatter.

Pseudocode Pattern

suite("Given <subject> with <state>", () => {
  setup_each(() => {
    // arrange
    // act
  })

  case("When <event> then <outcome>", () => {
    // assert only
  })
})

Anti-Patterns

• Nesting Given inside Given.
• Calling the SUT inside a case block when it can be executed in setup hooks.
• Mixing setup/action/asserts in a single case block.
• Adding wrapper suite blocks with no new context.
• Depth greater than suite -> suite -> case.

Review Checklist

• Are there any nested Given blocks?
• Does each case block contain assertions only?
• Is setup/action moved into setup hooks of the relevant scenario?
• Are single When + single Then cases collapsed into one case block?
• Is nesting depth <= 3?