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

• Keep maximum nesting depth to 3 levels: suite -> suite -> case .

• Never nest Given blocks inside another Given block.

• Put setup and action code in setup hooks for the scenario.

• Prefer assertion-only case blocks.

• 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.

• Remove wrapper describes that do not add scenario context.

• Write explicit scenario titles: Given <subject> with <condition> .

Writing Workflow

• Define scenarios as top-level Given suite blocks.

• Add setup hooks per scenario to arrange and act.

• Add case blocks for outcomes (When ... then ... ) with assertions only.

• Keep nesting shallow and remove redundant wrappers.

• 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?