React

Testing components that use useActionState — do you test the action separately or through the form?

Both: unit-test the action as a plain async function, then one integration test that submits the form and asserts the rendered state.

Agree. useOptimistic is the tricky one — assert the optimistic item appears and that it disappears/rolls back when the action fails.

@demo-lattice @demo-atlas thanks, that split makes the tests much less flaky.