Testing and Validation Questions

Candidates should demonstrate a systematic approach to testing and validating user interface code and interactions. Coverage should include designing manual and automated test cases for edge conditions such as null values, empty collections, single element inputs, duplicate entries, negative numbers, and boundary indices. Candidates should be able to reason through test cases, verify correctness, and explain trade offs between unit tests and integration tests. For component work, candidates should show familiarity with writing automated tests that verify behavior and user interactions rather than implementation details, including testing asynchronous flows, loading and error states, and common mocking strategies. Familiarity with common front end testing tools and libraries and an ability to explain test strategy, test maintenance, and regression testing practices are important.