Manual Testing Interview Questions India 2026: STLC

Testing lifecycle and process questions:

1. SDLC vs STLC: SDLC (Software Development Life Cycle): the process of building software: requirement analysis, design, implementation, testing, deployment, maintenance. STLC (Software Testing Life Cycle): the QA-specific subset: requirement analysis, test planning, test case design, test environment setup, test execution, defect reporting and tracking, test closure. STLC runs in parallel with SDLC, not after it. QA involvement in requirements phase (shift-left testing) catches defects early when they are cheapest to fix.

2. Verification vs validation: Verification: are we building the product right? (Are we following the requirements correctly?) Static testing: reviews, inspections, walkthroughs: done without executing code. Validation: are we building the right product? (Does it meet the user's actual needs?) Dynamic testing: executing the software. Verification happens first; validation confirms the final product meets business goals.

3. Types of testing: Functional: unit, integration, system, acceptance (UAT). Non-functional: performance (load, stress, soak), security, usability, compatibility. Regression: confirm existing features still work after a change. Smoke: high-level sanity check after a build (is the build testable?). Sanity: focused re-test of a specific bug fix or feature. Exploratory: unscripted; tester actively designs and executes tests simultaneously based on domain knowledge.

4. Testing levels: Unit testing: individual functions/methods; done by developers. Integration testing: multiple modules/services working together; checks API contracts and data flow. System testing: end-to-end testing of the entire application. User acceptance testing (UAT): business users verify the system meets requirements before go-live.

Test design is a key interview topic:

1. Equivalence class partitioning (ECP): Divide input data into partitions where values in the same partition are expected to behave the same way. Test one value from each partition. Example: age field (18-60 is valid): valid partition (18-60), invalid low partition (< 18), invalid high partition (> 60). Test 30, 10, 70, not every value.

2. Boundary value analysis (BVA): Defects cluster at boundaries. Test the boundary values and values just inside/outside. Example: age 18-60: test 17, 18, 19, 59, 60, 61. BVA is used with ECP: partition boundaries are the test points.

3. Decision table testing: For features with multiple conditions that combine to produce different outcomes. Create a table: columns are combinations of conditions (true/false), rows are conditions and expected actions. Ensures all valid condition combinations are covered. Example: login with correct/incorrect email and correct/incorrect password, 4 combinations, 4 test cases.

4. State transition testing: For systems that behave differently based on current state. Draw a state diagram: states (nodes) and transitions (edges triggered by events). Test: valid transitions, invalid transitions (trying to reach a state from an invalid starting state). Example: bank account states (active, dormant, closed) and transitions (deposit, withdraw, close).

5. Error guessing: Experience-based technique. Tester uses domain knowledge to guess likely error-prone areas. Examples: empty inputs, null values, special characters, very long strings, negative numbers, zero, duplicate data, concurrent access. Not a formal technique but highly effective for exploratory testing.

Practical testing skills tested in Indian interviews:

1. Bug life cycle: New: defect is discovered and logged. Assigned: assigned to the developer. Open: developer starts working on it. Fixed: developer marks as fixed. Re-test (Reopen/Closed): QA retests. If fixed: Closed. If not fixed: Reopened and the cycle repeats. Additional states: Rejected (not a defect, works as designed), Deferred (valid defect, will fix in a future release), Duplicate.

2. Severity vs priority: Severity: the impact of the defect on the system (Blocker, Critical, Major, Minor, Trivial). Technical perspective. Priority: how urgently the defect needs to be fixed (P1, P2, P3, P4). Business perspective. Examples of disconnect: a typo in the company name on the homepage, low severity (no functionality broken) but high priority (visible to all users). A critical crash in a rarely-used admin feature, high severity but lower priority (few users affected).

3. Good defect report attributes: Title: clear, concise, describes the actual vs expected behaviour. Steps to reproduce: numbered, specific, reproducible. Expected result: what should happen. Actual result: what happens. Severity and priority. Environment: browser version, OS, app version, test data used. Screenshots/screen recording. Attached logs. A defect that cannot be reproduced by the developer is a defect that does not get fixed.

4. Agile testing: In Agile/Scrum, QA is involved from sprint planning, not just testing at the end. Definition of Done includes QA sign-off. Testing in sprints: test each user story within the same sprint it is developed. Regression: automated regression suite run on every build (CI/CD). Exploratory testing: each sprint; testers explore the new functionality without a script. Shift-left: QA reviews acceptance criteria and design before coding begins.