When an interviewer asks, “How would you test a login page?” It feels like a simple question. Most engineers respond by immediately listing test cases: “I’d test a valid username and password, an invalid password, a locked account…”

This is the #1 mistake. It’s a reactive, checklist-style answer, and it fails to demonstrate what senior interviewers are truly looking for: strategic thinking.

A great answer isn't just a list of tests; it's a demonstration of your entire problem-solving process. You need to show that you are not just a tester, but a quality strategist. The key is to stop thinking about test cases and start thinking in terms of a testing framework.

I call it the "TESTED" framework, and it’s a systematic way to structure your answer for any "How would you test X?" scenario.

• T - Talk & Understand: Before you say anything else, ask clarifying questions. What are the business requirements? Are there performance or security considerations? This shows you don't make assumptions.
• E - Enumerate Test Types: List the broad categories of testing you would perform (e.g., Functional, UI, API, Performance, Security). This proves you think about quality from multiple dimensions.
• S - Strategize & Scope: Explain how you would prioritize your tests based on risk. What is the most critical user path that must work?
• T - Test Cases & Scenarios: Now you can provide a few high-impact examples of test cases (positive, negative, and edge cases).
• E - Environment, Tools & Data: Briefly describe the setup you would need.
• D - Define Success: Explain how you would measure the success of your testing effort.

By using a structured approach like this, you transform your answer from a simple list into a compelling demonstration of your professional process. You show the interviewer not just what you would test, but how you think—and that is what gets you the offer.