Question 1

How do you test Vue components with Vue Test Utils?

Accepted Answer

mount/shallowMount, set props, trigger events, assert emitted events and text. Prefer testing behavior. Use Testing Library Vue for a11y-oriented queries when possible.

Question 2

Testing Pinia stores?

Accepted Answer

createPinia + setActivePinia in beforeEach; call actions; assert state/getters. Mock API modules. Reset state between tests.

Question 3

How do you test composables that use lifecycle hooks?

Accepted Answer

wrap in a component harness or use dedicated helpers so onMounted runs. Assert cleanup on unmount. Mock timers for intervals.

Question 4

Snapshot tests — useful or harmful?

Accepted Answer

Useful for small pure presentational output; brittle for large templates. Prefer explicit assertions for critical behavior.

Question 5

E2E testing Vue apps?

Accepted Answer

Playwright/Cypress against real flows; seed data; avoid coupling to CSS class churn. Cover login, critical CRUD, routing. Run in CI.

Question 6

Mocking Vue Router in unit tests?

Accepted Answer

createRouter with memory history or stub useRouter/useRoute. Test navigation emits/guards separately from UI when needed.

Question 7

How do you test async components / Suspense?

Accepted Answer

Await flushPromises; stub async children when focusing parent; assert fallbacks. Don't leave dangling timers. Control resolved data.

Question 8

Lead: testing strategy for a Vue product team?

Accepted Answer

Unit for composables/stores, component tests for UI contracts, e2e for journeys; coverage on critical paths not vanity %. Share fixtures. Fail CI on flakes with quarantine process.

Testing Vue.js Interview Questions

Other Vue.js interview topics