Support for test implementation (fixed IDs for UI components)

[devtobi]

Is your feature request related to a problem? Please describe. For better testability (regarding E2E tests) we need a fixed property on interactive elements.

Describe the solution you'd like data-cy attribute on elements needed for testing. To enforce setting the attribute https://github.com/davidcalhoun/eslint-plugin-test-selectors might be suitable.

Describe alternatives you've considered

Additional context

[devtobi]

With Vue 3.5 and the new useId functionality this feature might solve this issue by providing incremental deterministic ids. See https://blog.vuejs.org/posts/vue-3-5#useid for information. Keep in mind we should combine this with a custom prefix which can be define via the configuration on the App instance (see https://github.com/vuejs/core/pull/11404 for further info). This should be done for both normal applications as well as webcomponents. For webcomponents see https://blog.vuejs.org/posts/vue-3-5#custom-elements-improvements

[devtobi]

A first test was very positive, however we should only use this feature if we don't have the requirements for individual object names, as the useId helper only generates static numbers.

[devtobi]

Additional note: Keep in mind generated IDs are only deterministic throughout the current page. If routed to a new page, IDs are generated freshly (and counting does not go up but start again at 0)