QA & Testing: interview questions and learning guide

Testing fundamentals

Testing is asking the product hard questions before customers do.

Testing checks that software does what was promised and does not break what already worked. A test case has a purpose, steps, data and an expected result. Smoke tests quickly check the build is sane, regression tests check old features still work, and acceptance tests confirm the business need. Testers think about normal, boundary and wrong inputs. Good testers report clearly and focus on risk, not on running every possible test.

Interview tip: Explain how you choose what to test first when time is short: by risk and by impact.

Test automation basics

Automate what you will repeat, not everything you can click.

Automation turns stable, repeated checks into scripts that run fast and often. Good candidates are smoke and regression checks on stable features. A framework organises tests, data and reports. Locators must be stable, and waits should be smart rather than fixed sleeps. Flaky tests that pass and fail without code changes waste trust, so they must be fixed or removed. Automation runs in a pipeline so every change is checked.

Interview tip: Say which tests you would not automate and why. That shows judgement.

API testing and bug reports

A good bug report lets a stranger see the bug in two minutes.

APIs let systems talk to each other, so testers check them directly without the screen. A request has a method, address, headers and body, and the response has a status code and data. Tests check codes, data, errors and security basics. A good bug report has a clear title, steps, expected and actual result, environment and evidence like logs or screenshots. Tracking tools follow a bug from new to fixed to closed.

Interview tip: Always include steps, expected result, actual result and evidence in a defect.

Severity is how badly the defect hurts the product. Priority is how soon it should be fixed, which also depends on business needs.

Test by risk: critical user journeys and recently changed areas first, then regression on related features, and tell stakeholders what was not covered.

A clear title, exact steps, expected and actual result, the environment and evidence such as logs or screenshots so anyone can reproduce it.

One time checks, fast changing screens, exploratory and usability testing, where the cost of automating is higher than the value.

Verification checks we built the product right against the specification. Validation checks we built the right product for the user's need.

A clear title, steps to reproduce, expected and actual result, environment, severity and evidence such as a screenshot or log.

Smoke testing is a quick check that the build basically works. Regression testing checks that old features still work after changes.

Testing at and around the limits of an input range, such as 17, 18 and 19 for an age limit of 18.

Automate stable, repetitive, high-value checks like regression and API tests. Keep exploratory and one-time checks manual.

Severity is the technical impact. Priority is how soon the business wants it fixed.

Sending requests to endpoints and checking status code, response body, headers, error handling and speed.

Valid and invalid credentials, empty fields, password rules, lockout, forgot password, session timeout, security and different browsers.