umbraco-unit-testing

Unit testing Lit web components in the Umbraco backoffice uses @open-wc/testing with web-test-runner to validate shadow DOM rendering, observable state changes, and context consumption in isolated environments.

Playwright is required for isolated unit testing of Umbraco extensions because web-test-runner relies on it to execute chromium browser tests for Lit elements and observable subscriptions.

Testing Umbraco context API consumption without end-to-end testing uses local mock-based imports for simpler pure-logic tests, or full Umbraco dist-cms import-map wiring for realistic context consumption validation.

Configuring web-test-runner for Lit element rendering and observable state changes requires a root SKILL.md with YAML frontmatter, correct Umbraco dist-cms import-map paths or local mocks, and a deterministic test setup supporting Playwright execution.

Umbraco backoffice component tests fail on observable state changes when lacking a deterministic test setup with proper @open-wc/testing configuration and correct import-map paths for context consumption validation.

@open-wc/testing validates shadow DOM output and reactivity for Umbraco Lit elements by testing rendering behavior and observable state changes in fast, isolated unit tests rather than slow end-to-end testing.