Tested Application Step 6: The Frontend Suite

Write component tests for the parts of your interface that carry behavior: the four states, the form validation, the callback arguments, and the keyboard path. Query by role and label only, and where you cannot, fix the component rather than the test. Then deliberately break one behavior and confirm the right test fails. Finally, count how many of your tests would survive a complete rewrite of the component's internals; the ones that would not are testing the wrong thing.