testId

Testid refers to a practice in software testing where elements in a user interface are annotated with stable identifiers to facilitate automated tests. The most common implementation is the data-testid attribute used in web applications. Test IDs are not part of the user interface and are intended for test tooling rather than end users.

In practice, developers add data-testid attributes to elements, for example data-testid="submit-button". Testing frameworks provide selectors to locate elements by testId, such as getByTestId('submit-button') or equivalent methods in different libraries. These attributes enable tests to reliably find elements even when visual text, styling, or markup structure changes.

Rationale for using testids includes improving test robustness by decoupling selectors from presentation details like class names or visible text. This can help maintain test stability across UI refactors that do not affect the element’s behavior.

Best practices commonly recommended include keeping testids stable, ensuring they are unique within a page or component, and making them descriptive of the element’s purpose. It is also advised to avoid exposing sensitive data in testids and to prefer accessible selectors (such as aria-labels, roles, and visible text) when possible. Testids should typically be used to support UI behavior testing rather than as the sole means of interacting with the interface.

Limitations and cautions include the risk of brittle tests if testids are changed without coordinated updates, and the possibility that build processes may remove or alter data-testid attributes in production unless configured otherwise. Developers often adopt a policy that reserves testids for testing needs and complements them with accessibility-focused selectors.