Good QA engineers think about risk, not just clicking buttons. These questions check whether a candidate designs tests strategically and automates the right things.
Hiring a QA / Test Automation developer is easy. Telling a real one from a convincing résumé is the hard part — and it’s most of what we do. These are grouped by level, because the same question that stretches a junior is a warm-up for a senior.
Junior QA / Test Automation interview questions
0–2 years
Testing fundamentals.
What is the difference between verification and validation?
Verification checks you built it right (to spec); validation checks you built the right thing (meets the need).
Uses the terms interchangeably.
What are the levels of the test pyramid?
Many fast unit tests, fewer integration tests, and a few end-to-end tests — balancing speed, cost and confidence.
Wants to test everything through the UI.
What is the difference between a test case and a test plan?
A test case is a specific scenario with steps and expected results; a test plan is the overall strategy and scope.
Cannot distinguish strategy from individual cases.
What is regression testing?
Re-running tests to confirm existing behaviour still works after changes, ideally automated.
Only tests the new feature and ignores regressions.
What is the difference between functional and non-functional testing?
Functional checks what the system does; non-functional checks how (performance, security, usability).
Only considers functional behaviour.
What is black-box vs white-box testing?
Black-box tests behaviour without internal knowledge; white-box uses code structure to design tests.
Doesn’t know either approach.
What makes a good bug report?
Clear steps to reproduce, expected vs actual, environment, severity and evidence, so it’s actionable.
Writes “it doesn’t work” with no detail.
What are boundary value and equivalence partitioning?
Techniques to pick high-value inputs: test at boundaries and one representative per class instead of exhaustively.
Tests random inputs with no method.
Mid-level QA / Test Automation interview questions
2–5 years
Automation and strategy.
What should and shouldn’t you automate?
Automate stable, high-value, repetitive checks; leave exploratory and rapidly-changing UI to manual testing.
Tries to automate everything, including volatile UI.
How do you keep automated tests reliable?
Deterministic setup/teardown, stable selectors, waiting on conditions not timers, and isolating test data.
Uses fixed sleeps and shares mutable state between tests.
What causes flaky tests and how do you handle them?
Timing, order dependence, shared state and external dependencies; quarantine and fix rather than blindly retry.
Reruns until green and ignores the root cause.
How do you design a maintainable UI test suite?
Patterns like Page Objects/screenplay, stable locators, and minimal end-to-end coverage over critical journeys.
Duplicated selectors and brittle tests across the suite.
How does test data management work?
Isolated, reproducible data per test via factories/fixtures or seeding, avoiding reliance on shared environments.
Depends on manually-created data in a shared environment.
How do you test an API?
Validate status codes, schemas, edge cases, auth and error handling, ideally automated and independent of the UI.
Only tests via the UI.
How do tests fit into CI/CD?
Fast tests gate every change; slower suites run on schedules or pre-release, with clear signal on failure.
Tests run manually and rarely.
What is the difference between mocks, stubs and fakes?
Test doubles differing in behaviour: stubs return canned data, mocks assert interactions, fakes are lightweight working implementations.
Uses the terms interchangeably and over-mocks.
Senior QA / Test Automation interview questions
5+ years
Quality strategy.
How do you build a quality strategy for a team?
Shift-left testing, a balanced automation pyramid, clear ownership, risk-based coverage, and quality as a shared responsibility.
Treats QA as a gate at the end that catches everything.
How do you measure test effectiveness?
Escaped-defect rate, coverage of critical paths, flakiness and feedback speed — not just raw coverage percentage.
Chases 100% code coverage as the only metric.
How do you approach performance and load testing?
Define SLOs, model realistic load, test early and continuously, and analyse bottlenecks rather than just pass/fail.
Runs a load test once before launch, if at all.
How do you test in a microservices architecture?
Contract testing between services, plus targeted integration and a thin layer of end-to-end journeys.
Relies solely on brittle full end-to-end tests.
How do you prevent the test suite from becoming a bottleneck?
Parallelisation, test selection, trimming redundant tests, and keeping the pyramid healthy so feedback stays fast.
Lets a slow suite balloon until people skip it.
How do you balance manual and automated testing?
Automate regression and repetitive checks; invest human effort in exploratory testing and areas of high risk and change.
Believes automation removes all need for manual testing.
How do you embed quality earlier in the process?
Involve QA in design and acceptance criteria, add tests to definition of done, and catch issues before code is written.
Only engages after development is “done.”
How do you handle testing in a fast-moving startup?
Risk-based prioritisation, automating the critical few, and pragmatic coverage rather than exhaustive testing.
Insists on exhaustive coverage that stalls delivery.
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