Test infrastructure. Playwright visual regression (E2E with Figma CDP reference), bun:test unit tests, no-chrome test mode, data-ready synchronization, and page reuse optimization.
### Requirement: Component-instance sync unit tests
Unit tests SHALL cover the component-instance sync lifecycle: instance creation with `componentId` mapping on children, sync propagation of property changes, override preservation during sync, new child addition to instances, and detach breaking the link.
#### Scenario: Instance child mapping test
- **WHEN** `bun test ./tests/engine/scene-graph.test.ts` runs
- **THEN** the test verifies instance children have `componentId` pointing to component children
#### Scenario: Sync propagation test
- **WHEN** a component's text child changes and sync is triggered
- **THEN** the test verifies instance children receive the updated text and fontSize
#### Scenario: Override preservation test
- **WHEN** an instance child has an overridden text value
- **THEN** the test verifies the override is preserved while non-overridden properties sync
#### Scenario: New child addition test
- **WHEN** a new child is added to a component and sync runs
- **THEN** the test verifies existing instances gain the new child
#### Scenario: Detach test
- **WHEN** an instance is detached
- **THEN** the test verifies type becomes FRAME, componentId is null, and the component's instance list no longer includes it
Unit tests SHALL cover the variables system: add and resolve color/number variables, alias chain resolution, circular alias detection (returns undefined), mode switching, bind/unbind to nodes, and variable removal cleanup. Total: 7 variable tests in a "Variables" describe block.
#### Scenario: Variable tests pass
- **WHEN** `bun test ./tests/engine` is run
- **THEN** all variable tests pass (add/resolve color, resolve number, alias chain, circular alias, mode switching, bind/unbind, removal cleanup)
The test suite SHALL include roundtrip tests for real .fig files: parsing property invariants, encode/decode cycle fidelity. Test fixtures (material3.fig, nuxtui.fig) SHALL be tracked via Git LFS.
#### Scenario: Roundtrip encode/decode
- **WHEN** a .fig file is parsed and re-encoded
- **THEN** the re-encoded data decodes to the same node properties
#### Scenario: Property invariants
- **WHEN** a real .fig file is parsed
- **THEN** all nodes have valid types, dimensions ≥ 0, and required fields present
### Requirement: .fig import performance
The .fig import pipeline SHALL avoid O(n²) child resolution. A children index SHALL be built upfront for linear-time lookups.
#### Scenario: Large file import speed
- **WHEN** material3.fig (87K nodes) is imported
- **THEN** parsing completes in under 2 seconds (was 37s before fix)
### Requirement: JSX renderer tests
The test suite SHALL include tests for the JSX renderer covering all node types (Frame, Text, Rectangle, Ellipse, etc.), layout props, effects, and nesting. Currently 27 tests.
#### Scenario: Render Frame with children
- **WHEN** a JSX tree with Frame containing Rectangle and Text is rendered
- **THEN** the scene graph contains correct parent-child relationships and properties
The test suite SHALL include Playwright e2e tests for the AI chat panel with mock transport (no real LLM calls). Tests cover: sending a message, receiving a response, tool call display. Real LLM tests available via TEST_REAL_LLM=1 flag.
#### Scenario: Chat with mock transport
- **WHEN** a Playwright test sends a message via the chat input
- **THEN** the mock transport returns a response and the message appears in the chat
### Requirement: JSX export tests
The test suite SHALL include tests for sceneNodeToJsx() covering shapes, text, layout props, effects, and multi-selection. Currently 14 tests.
#### Scenario: Export rectangle to JSX
- **WHEN** sceneNodeToJsx is called on a rectangle with blue fill
- **THEN** the output includes Rectangle component with bg prop
