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Software Testing Interview Questions in Kolkata

36 practice questions with answers for Software Testing interviews in Kolkata.

Software Testing jobs in Kolkata

Kolkata has a steady IT-services and BFSI technology job market around Salt Lake Sector V and New Town. Many openings are with service companies and their delivery centres, with a focus on strong fundamentals.

Below are 36 questions that match the mix of service, product and domain employers hiring software testers in Kolkata.

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What is the difference between statement coverage and branch coverage?

Test Case DesignMedium

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Statement coverage measures the percentage of code statements executed by tests. Branch coverage measures whether every decision outcome, true and false, has been executed. Branch coverage is stronger: for 'if (amount > 1000) applyDiscount()', one test with 1500 gives 100 percent statement coverage, but you need a second test with 500 to cover the false branch. 100 percent branch coverage implies 100 percent statement coverage, not the other way round.

You notice full card numbers printed in the application logs. What do you do?

Performance and Security BasicsMedium

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Treat it as a high-severity security defect, because storing full card numbers in logs breaks payment card security rules and creates a data leak risk. Do not copy the card numbers into the bug; use masked examples and the log location instead. Log the bug with restricted visibility and inform your lead and the security contact right away. After the fix, verify new logs are masked and confirm old logs are cleaned.

How do you test API error handling for invalid input?

Agile, SQL and API TestingMedium

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Send requests with missing required fields, wrong data types, values beyond limits, invalid formats such as a bad email, unknown fields and an empty or malformed JSON body. The API should return a 4xx code such as 400 or 422, a clear error message that names the field, and no stack trace or database details. Also check that nothing was partly saved in the database after the failed request.

Tell me about a time you found an important bug that others missed.

Manual Testing BasicsMedium

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Model answer: Situation: before a release of an insurance app, all regression tests had passed. Task: I was doing a final exploratory round. Action: I renewed a policy on the last day of the month and saw that the premium was calculated for 31 days in a 30-day month. I logged it with exact data and the formula difference. Result: the date logic was fixed before release, and I added month-end cases to the suite.

What is the difference between smoke testing in CI and full regression?

Testing TypesMedium

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Smoke tests run on every build for quick feedback; full regression runs less often, such as nightly or before release.

A security scan says your login page can be loaded inside a frame on other sites. What is the risk and how do you confirm it?

Performance and Security BasicsHard

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Clickjacking tricks a user into clicking something on your site while it is hidden inside a frame on an attacker's page, for example a hidden Transfer button under a fake Play button. A tester checks whether sensitive pages can be loaded in an iframe on another site, and inspects response headers for Content-Security-Policy frame-ancestors or X-Frame-Options set to DENY or SAMEORIGIN. If the page loads in the frame, log it.

What is the difference between a bug and an enhancement?

Bug Life Cycle and JiraMedium

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A bug is behaviour that deviates from agreed requirements; an enhancement is a new or improved capability beyond the current requirements.

An API returns 200 OK but the body contains an error message. Is that a bug?

Agile, SQL and API TestingMedium

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Usually yes. Status codes should reflect the result so clients and monitoring can react correctly; an error with 200 can hide failures and break retries. A validation error should return 400 or 422, a missing resource 404 and a server failure 500. Check the API contract first: some legacy APIs document this pattern. If it is not documented, log it as a defect with the request and response attached.

What are the main testing differences between Android and iOS?

Mobile TestingMedium

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Android has many manufacturers, screen sizes and OS versions with custom skins, so device fragmentation and background-kill behaviour need more coverage. iOS has fewer devices but strict permission, privacy and store review rules. Navigation differs: Android has a system back button or gesture, iOS relies on in-app navigation and swipe back. Notification, permission and file-access behaviours also differ, so test cases need platform-specific steps.

What is root cause analysis for defects?

Bug Life Cycle and JiraMedium

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Finding why a defect was introduced, such as unclear requirements or missed reviews, to prevent similar defects in future.

What is scalability testing?

Performance and Security BasicsMedium

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Scalability testing checks how well the system handles growing load by adding resources, such as more servers or bigger machines, and whether performance improves in proportion. For example, if two servers handle 1,000 users, do four servers handle about 2,000 at the same response time? It finds limits that resources cannot fix, such as a single database bottleneck, and helps plan capacity for future growth.

What is use case testing?

Test Case DesignMedium

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Designing tests from user flows described in use cases to verify complete real-world interactions.

What is JQL?

Bug Life Cycle and JiraMedium

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JIRA Query Language, used to search issues, for example project = ABC AND status = Open AND priority = High.

What goes into a test plan?

STLC and Test PlanningMedium

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Scope (in and out), objectives, approach, environments, schedule, roles, entry/exit criteria, risks and mitigation, deliverables and tools.

What is cause-effect graphing?

Test Case DesignHard

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Cause-effect graphing is a black box technique that models input conditions (causes) and output actions (effects) with logical relations like AND, OR and NOT. The graph is converted into a decision table, and each column becomes a test case. It is useful when outputs depend on combinations of inputs, such as loan approval based on income, age and credit score. It helps find missing or contradictory rules in the requirement.

Write test cases for a search box.

Test Case DesignMedium

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Valid keyword, partial match, no results, special characters, very long text, empty search, case sensitivity, spelling errors, suggestions and speed of results.

What is the difference between a test suite and a test run?

STLC and Test PlanningMedium

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A suite is a collection of related test cases; a run is one execution of a set of tests against a build.

A web app gets slower the longer a user keeps it open. How do you check for a memory leak as a manual tester?

Performance and Security BasicsHard

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A memory leak happens when an application keeps holding memory it no longer needs, so usage grows the longer it runs. A manual tester may notice the app getting slower over a long session, a browser tab using more and more memory in Task Manager or the browser's memory panel, or a mobile app crashing after repeatedly opening and closing a screen. Report the steps, duration and memory readings over time.

What is heuristic evaluation and how is it different from a usability test with users?

Accessibility & Usability TestingMedium

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Heuristic evaluation is an expert review where a few evaluators inspect the interface against known usability principles, such as Nielsen's ten heuristics, and list problems with severity. It is fast and cheap and needs no participants. A usability test watches real users perform tasks and shows where they actually struggle. Heuristic reviews find many obvious issues early, but they can miss problems that only real users with real goals reveal.

How do you break a requirement into testable conditions?

Manual Testing BasicsMedium

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Read the requirement and identify inputs, outputs, business rules, user roles and states. Turn each rule into a condition with an expected result, then add negative and boundary conditions. For example, 'users can withdraw up to 10,000 per day' becomes: withdraw below the limit, exactly at the limit, above the limit, multiple withdrawals adding up to the limit, and the limit resetting the next day. Each condition then becomes one or more test cases.

Why do performance reports use percentiles like p90 and p95 instead of averages?

Performance and Security BasicsMedium

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An average hides slow requests. If 90 requests take 1 second and 10 take 10 seconds, the average is 1.9 seconds, which looks fine, but one user in ten waits 10 seconds. The p95 value means 95 percent of requests were faster than it, so it shows what most users actually experience, including the slow tail. Service level targets are usually written as percentiles, such as p95 under 2 seconds.

What is exploratory testing?

Testing TypesMedium

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Learning, test design and execution at the same time, without scripted cases — time-boxed sessions with a charter (e.g. 'explore checkout with coupons'), noting bugs and ideas. Great for finding edge cases.

A dashboard shows pass or fail status only with red and green dots. What is the issue?

Accessibility & Usability TestingEasy

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This relies on colour alone to give information, which fails WCAG criterion 1.4.1. Users with red-green colour blindness, which affects a noticeable share of men, cannot tell the states apart, and screen readers announce nothing. Recommend adding text or icons such as a tick and a cross with labels like 'Passed' and 'Failed', and accessible names for the dots. Test with a colour blindness simulator in browser developer tools.

What is regression testing, and when do you automate it?

Testing TypesMedium

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Re-testing existing features after a change. Automate stable, repetitive, high-value flows that run every release.

What is a test condition?

Test Case DesignEasy

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A test condition is an item or event of the system that can be verified by one or more test cases, derived from the test basis. For example, for a login requirement, conditions include valid login, wrong password, locked account and remember me. Test conditions answer what to test, while test cases describe how to test it with steps, data and expected results. Listing conditions first helps check coverage before writing detailed cases.

How do you capture screenshots, videos and traces when an automated test fails?

Automation Basics for Manual TestersMedium

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Most frameworks support this through configuration. In Playwright, set screenshot to only-on-failure, video to retain-on-failure and trace to on-first-retry in the config, then open the trace viewer to step through actions, network calls and the page state. In Selenium, call save_screenshot in a teardown hook when a test fails. Store these artefacts in CI so anyone can debug the failure without rerunning it.

What is mobile app testing and what extra checks does it need?

Mobile TestingMedium

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Test on real devices and OS versions, interrupts such as calls, battery, network changes, gestures, permissions and app store guidelines.

When is manual testing a better choice than automation?

Manual Testing BasicsEasy

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Manual testing is better for exploratory testing, usability and look-and-feel checks, features that change often, one-time tests and early testing of new functionality. Automation pays off for stable, repetitive tests such as regression suites, data-driven checks and smoke tests run on every build. Most teams combine both: manual for discovery and judgement, automation for speed and repeatability.

Write test cases for a file upload feature.

Test Case DesignMedium

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Allowed and disallowed formats, size limits, empty file, duplicate names, special-character names, cancel upload, slow network and multiple files.

How do you write steps to reproduce for a bug that needs specific test data?

Bug Life Cycle and JiraMedium

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Start with preconditions: environment, build number, user role and the exact data state, such as an account with two pending orders and zero wallet balance. Mention how to create the data or give the test account ID. Then list numbered steps with exact inputs and finish with expected and actual results. If the data is hard to set up, attach the SQL used or a database screenshot so the developer can recreate it quickly.

How do you test a database trigger?

Database TestingMedium

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First read what the trigger should do and when it fires, such as AFTER UPDATE on the salary column writing a row to an audit table. Then perform the event that should fire it and query the target table to confirm the expected row and values. Also perform events that should not fire it and confirm nothing happens. Check multi-row updates, NULL values and rollback: if the main statement fails, the trigger's changes must not remain.

A report shows duplicate rows after a new release. How do you investigate in the database?

Database TestingMedium

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Run the report query with GROUP BY on the business key and HAVING COUNT(*) > 1 to find which records repeat. Then check whether the duplicates exist in the base table or are created by the query, usually a new join to a one-to-many table such as addresses. Compare the query before and after the release. Include the duplicate keys, the count and the suspected join in the bug report.

What is JMeter and what does a basic test plan in it contain?

Performance and Security BasicsHard

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Apache JMeter is an open-source load testing tool, mainly for HTTP APIs and web pages. A basic test plan has a Thread Group that sets the number of virtual users, ramp-up time and loop count; samplers such as HTTP Requests; config elements like headers and CSV data; timers for think time; assertions on responses; and listeners or reports showing response times, throughput and errors. Run real load in non-GUI mode.

Write test cases for an OTP verification screen.

Test Case DesignMedium

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Verify a correct OTP within validity logs the user in. Verify a wrong OTP shows an error and an expired OTP is rejected. Check the OTP length and that only digits are allowed. Test resend: it is disabled during the countdown, and the old OTP stops working after resend. Check the maximum number of wrong attempts locks verification. Verify auto-read on mobile, paste support, and behaviour when the network drops during submission.

Tell me about a time you pushed for an accessibility fix the team wanted to postpone.

Accessibility & Usability TestingMedium

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Situation: before a release, I found the payment form errors were not announced by screen readers and not reachable by keyboard. Task: the team wanted to defer it. Action: I recorded a short NVDA video showing a user could not finish payment, linked it to WCAG and our customer commitments, and proposed a small fix. Result: the fix took half a day, shipped in the release and we added keyboard checks to our definition of done.

What is think time in performance testing?

Performance and Security BasicsEasy

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Think time is the pause a real user takes between actions, such as reading a product page before adding it to the cart. Performance scripts add think time, often with random variation, so virtual users behave realistically. Without think time, a few virtual users generate a load equal to many real users, which gives misleading results. Think time values are usually taken from analytics or production logs.