web-component-testing

# Web Component Testing Use Playwright in a real browser for `fig-*` components. Avoid jsdom for component behavior because this repo depends on Custom Elements, layout, focus, dialogs, pointer events, media elements, and CSS. ## Contract Priorities 1. Assert registration with `customElements.get(tag)` or customized built-in upgrade. 2. Mount representative markup and wait for `customElements.whenDefined(tag)`. 3. Fail on page errors and unexpected console errors. 4. Test both attribute writes and property writes for value-like APIs. 5. Capture `input`, `change`, and component-specific events from real interactions. 6. Assert `event.detail` shape for data controls. 7. Verify disabled controls do not emit normal interaction changes where applicable. ## Interaction Pattern - Prefer user-like interactions: `click`, `keyboard`, pointer drag, native input dispatch. - Use host properties for public APIs: `el.value`, `el.checked`, `el.selected`, `el.open`. - Use internal DOM only when no public interaction exists. - Keep each failure tagged with component name and scenario id. ## Fixture Guidance - Keep fixtures minimal and deterministic. - Include required children for compound controls. - Avoid network-dependent assertions; external media URLs are acceptable for smoke fixtures but not for pass/fail timing. - For customized built-ins, create with markup such as `<dialog is="fig-dialog">`.