Curated interview practice questions with answers. These are practice scenarios, not a verified list of past interview questions.
About Cognizant hiring for ISTQB roles
Cognizant is a US-headquartered IT services and consulting company with most of its workforce based in India. It provides application development, testing, cloud, digital engineering and data analytics services, with strong practices in healthcare, insurance and banking. In India it hires for programmer analyst, quality engineer and data roles through campus and off-campus programmes such as GenC.
For ISTQB roles, this Cognizant practice set focuses most on Test Tools and Exam Preparation (5), Testing Throughout the SDLC (5), White-Box, Experience and Collaboration-Based Testing (4), Fundamentals of Testing (4). It has 17 easy, 10 medium, 3 hard questions, so you can start easy and work up to the harder ones.
Company type
IT services
Headquarters
Teaneck, New Jersey, USA
Main India offices
Chennai, Bengaluru, Pune, Hyderabad, Kolkata
Cognizant ISTQB interview process
Online assessment (aptitude + reasoning)
Coding assessment
Technical interview
HR round
Typical pattern based on public candidate experiences. Rounds vary by role, team and year.
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01
Explain equivalence partitioning and its coverage.
Equivalence partitioning divides data into partitions whose values are expected to be processed the same way, so one value per partition is enough. Partitions can cover inputs, outputs, configuration items or time, and include valid and invalid partitions. They must be non-empty and must not overlap. Coverage is partitions exercised divided by partitions identified. With several inputs, Each Choice coverage requires every partition of every input to be used at least once.
White-box testing considers the whole implementation, so it can find defects even when the specification is vague, outdated or incomplete. Coverage gives an objective measure of thoroughness. It can also be used in static testing, for example dry runs of code or pseudocode. Its main weakness is that it cannot detect omissions: if a requirement was never implemented, no white-box test will notice it.
03
What is checklist-based testing and what are its risks?
In checklist-based testing, the tester designs and runs tests to cover the conditions on a checklist built from experience, user needs or knowledge of why software fails. Items should be specific and testable, not vague or automatable by tools. Checklists give some consistency and guidance when detailed test cases are missing, but they become less effective over time as developers learn to avoid those mistakes, so they must be updated regularly.
04
Write a test charter for an exploratory session on a checkout page.
Charter: Explore the checkout page with different coupon and payment combinations to discover pricing and rounding errors. Time box: 60 minutes. Focus areas: coupon stacking, expired coupons, quantity changes after applying a coupon, currency rounding, and using the browser back button. Record test ideas, defects, questions and areas covered. Debrief with the test lead after the session to agree next charters.
05
What do the K-levels K1, K2 and K3 mean in the CTFL syllabus?
K-levels describe the cognitive level of each learning objective. K1 is remember: recall a term or fact, such as listing test levels. K2 is understand: explain, compare, classify or give examples, such as distinguishing project and product risks. K3 is apply: use a procedure in a given situation, such as deriving boundary values or calculating a three-point estimate. Most exam questions are K2.
06
How does testing relate to quality assurance and quality control?
Testing is a form of quality control (QC): a product-oriented, corrective approach that checks work products. Quality assurance (QA) is process-oriented and preventive: it improves processes on the idea that a good process produces a good product. Test results are used by both. QC uses them to fix defects, and QA uses them as feedback on how well the development and test processes are performing.
07
What information does a defect report typically contain in CTFL v4.0?
A unique identifier; a title with a short summary; date observed, issuing organisation and author; the test object and test environment; context such as test case, test activity and test data; a description for reproduction with steps, logs, screenshots, and expected and actual results; severity; priority; status such as open, deferred, duplicate, re-opened, closed or rejected; and references, for example to the test case.
Shift-left means performing testing earlier in the SDLC. Practices include reviewing specifications from a tester's perspective, writing test cases before code, using CI/CD for fast feedback, running static analysis before dynamic testing and starting non-functional testing at component level. It costs extra effort early, but saves much more later, because a defect found in requirements is far cheaper to fix than one found in production.
Component testing checks individual units in isolation. Component integration testing checks interfaces and interactions between components. System testing checks overall behaviour, both functional and non-functional. System integration testing checks interfaces with other systems and external services. Acceptance testing focuses on validation and readiness for deployment. Each level has its own objectives, test basis, test objects, typical defects and responsibilities.
10
Order these tests for execution: A (priority 1, depends on C), B (priority 2), C (priority 3), D (priority 2, depends on B). 1 is highest.
A has the highest priority but depends on C, so C must run first, followed by A. Next come the priority 2 tests: B, then D, because D depends on B. The execution order is C, A, B, D. ISTQB exams often include such questions; always satisfy dependencies first, then follow priority, and run the highest priority test as early as its dependencies allow.
11
What test case prioritisation strategies are there?
Risk-based prioritisation orders tests by the results of risk analysis, running tests for the highest risks first. Coverage-based prioritisation orders by coverage, running tests that achieve the most coverage first; additional coverage prioritisation picks each next test by the extra coverage it adds. Requirements-based prioritisation follows the priorities of requirements set by stakeholders. Dependencies can force a lower-priority test to run first.
The manager decides what is reviewed and provides resources. The author creates and fixes the work product. The moderator, or facilitator, ensures meetings run effectively, mediating and managing time. The scribe, or recorder, collects anomalies and records decisions. Reviewers perform the review and may be team members, experts or stakeholders. The review leader takes overall responsibility, deciding who is involved and organising the review. One person can hold several roles.
1) Testing shows the presence, not the absence, of defects. 2) Exhaustive testing is impossible, so use test techniques, prioritisation and risk. 3) Early testing saves time and money. 4) Defects cluster together in a few components. 5) Tests wear out, so update them or write new ones. 6) Testing is context dependent. 7) Absence-of-defects fallacy: a defect-free system can still fail if it does not meet user needs.
14
Show the TDD red-green-refactor cycle with a small example.
# Red: write a failing test first
def test_discount():
assert discount(1000) == 100
# Green: simplest code that passes
def discount(amount):
return amount * 0.10
# Refactor: improve design, test stays green
RATE = 0.10
def discount(amount):
return round(amount * RATE, 2)
Repeat the cycle for each new behaviour, such as no discount below 500.
15
Explain error, defect, failure and root cause with an example.
A human makes an error (mistake), for example misreading a requirement. The error produces a defect (fault or bug) in a work product such as code or a document. When defective code is executed it may cause a failure, meaning the system does something wrong or fails to do something. The root cause is the fundamental reason for the error, such as time pressure or unclear requirements. Failures can also come from environmental conditions like radiation.
16
A company uses its own testing terms that differ from ISTQB terms. How do you handle this in the exam and at work?
In the exam, always answer using the ISTQB syllabus and glossary definitions, because questions are written from them. At work, I would map local terms to ISTQB ones, for example 'sanity check' to a smoke test, and help the team build a shared glossary. A common vocabulary reduces misunderstandings, especially when working with distributed teams or clients.
17
What is the difference between testing and debugging?
Testing triggers failures caused by defects (dynamic testing) or finds defects directly in work products (static testing). Debugging is a development activity that reproduces a failure, diagnoses the root cause and fixes the defect. After the fix, testers run confirmation testing to check the fix and regression testing to check nothing else broke. In short, testing finds and reports problems, while debugging locates and removes them.
18
What changed in CTFL v4.0 compared with the 2018 syllabus?
v4.0 added Agile and DevOps content: the whole team approach, test-first approaches like TDD, ATDD and BDD, shift-left, retrospectives, collaboration-based test approaches, the test pyramid and testing quadrants. It renamed the pesticide paradox to 'tests wear out', removed use case testing and decision coverage, focused white-box testing on statement and branch coverage, and described test roles instead of job titles.
19
A tester logs a defect titled 'Login broken' with no other details. How would you improve it?
A better title is 'Login - valid credentials - error 500 after clicking Sign in'. The report should add the build number and environment, browser and device, preconditions such as user type, numbered steps, test data used, expected result, actual result with the error message, a screenshot or log, severity, suggested priority, and a reference to the related test case. This lets a developer reproduce it immediately.
20
In a review, what is the difference between an anomaly and a defect?
Reviewers log anomalies: observations that differ from what they expected. Not every anomaly is a defect; some turn out to be misunderstandings, open questions or improvement suggestions. During communication and analysis the team decides each anomaly's status, owner and required action, and confirmed ones become defects for the author to fix. This keeps reviews constructive instead of treating every comment as the author's mistake.
21
What categories of test tools does CTFL v4.0 describe?
Test management tools, static testing tools, test design and implementation tools, test execution and coverage tools, non-functional testing tools, DevOps tools such as CI/CD pipelines and build tools, collaboration tools, and tools supporting scalability and deployment standardisation such as virtual machines and containers. Any tool that assists testing counts, even a spreadsheet. Tools improve efficiency, quality and repeatability.
A retrospective is held at the end of an iteration, release or project to discuss what went well, what did not and how to improve. For testing, the benefits include more effective and efficient testing, better testware, team bonding, better quality of the test basis and stronger cooperation between developers and testers. Results should be recorded and the improvement actions tracked so that they are actually carried out.
23
What is branch testing and how is branch coverage measured?
A branch is a transfer of control between two nodes in the control flow graph. Branches can be unconditional, like straight-line code, or conditional, like the true and false outcomes of an if or the cases of a switch. Branch coverage = branches exercised / total branches x 100. Branch testing designs tests so that every branch, including the hidden false path of an if without else, is exercised.
24
How are CTFL v4.0 exam questions distributed across chapters?
Approximately: Chapter 1, Fundamentals of Testing, 8 questions; Chapter 2, Testing Throughout the SDLC, 6; Chapter 3, Static Testing, 4; Chapter 4, Test Analysis and Design, 11; Chapter 5, Managing the Test Activities, 9; Chapter 6, Test Tools, 2. Chapters 4 and 5 carry half the marks and include most K3 questions, so practise techniques and estimation thoroughly.
25
Why is early and frequent stakeholder feedback important?
Early and frequent feedback catches misunderstandings about requirements before they become expensive. Without it, the product may not match what stakeholders want, leading to costly rework, missed deadlines, blame games and even project failure. Regular feedback through reviews, demos and backlog refinement keeps the team focused on the most valuable features and builds a shared understanding of what is being built.
26
Why does CTFL v4.0 recommend starting non-functional testing early?
Non-functional tests are often left to the end, but late discovery of performance or security problems can threaten the whole project. v4.0 recommends starting early, even at component level, for example measuring response time of a key service. Some tests need special environments such as a usability lab. Many non-functional tests reuse functional tests but measure a different quality, like checking login speed under 500 concurrent users.
27
Historically, development and test effort are in the ratio 3:2. Development is estimated at 600 person-days. Estimate the test effort.
This is estimation based on ratios. Test effort = development effort x 2 / 3 = 600 x 2 / 3 = 400 person-days. The ratio must come from similar past projects in the same organisation, because it changes with domain, risk and process maturity. I would also cross-check with another technique, such as Wideband Delphi, before committing to the number.
28
A field accepts integers from 1 to 99. Which set of values achieves 100 percent 2-value BVA coverage: {1, 99}, {0, 1, 99, 100}, {0, 50, 100} or {1, 2, 98, 99}?
The answer is {0, 1, 99, 100}. Two-value BVA needs each boundary value and its closest neighbour in the adjacent partition: 0 and 1 at the lower edge, 99 and 100 at the upper edge. {1, 99} misses the invalid neighbours, {0, 50, 100} misses 1 and 99, and {1, 2, 98, 99} stays inside the valid partition, which is closer to 3-value thinking.
29
Which black-box test techniques are covered in CTFL v4.0?
CTFL v4.0 covers four black-box techniques: equivalence partitioning, boundary value analysis (2-value and 3-value), decision table testing and state transition testing. They derive tests from the specification without looking at the internal structure, so tests stay valid even when the implementation changes. Use case testing, which was in older syllabi, is no longer part of the v4.0 Foundation syllabus.
30
A module of 15,000 lines of code has 45 defects. Calculate its defect density and explain how you would use it.
Defect density = defects / size = 45 / 15 KLOC = 3 defects per KLOC. If other modules average 1 defect per KLOC, this module is a defect cluster, so I would increase test depth there, ask for a code review or refactoring, and add more regression tests. Compare density only across similar code, because language and complexity affect the numbers.
Tips to crack the Cognizant ISTQB interview
Understand the GenC, GenC Next and GenC Elevate tracks so you know which skills and coding level each role expects.
Revise SQL queries, OOP concepts and basic testing terminology since many freshers are placed in development or QA projects.
Read about Cognizant's healthcare and life sciences domain work, which is a large part of its client base.
Keep a one-minute story ready for every project on your CV: problem, your part, tools, result.
Practise the hard questions on this page aloud; Cognizant interviewers usually ask follow-ups on your first answer.
Frequently asked questions
How many rounds are there in the Cognizant ISTQB interview?
Candidates usually go through 4 stages: Online assessment (aptitude + reasoning); Coding assessment; Technical interview; HR round. The exact rounds change with the role, team, location and your experience, so confirm the process with the recruiter.
Which topics should I prepare for the Cognizant ISTQB interview?
This practice set leans on Test Tools and Exam Preparation (5), Testing Throughout the SDLC (5), White-Box, Experience and Collaboration-Based Testing (4), Fundamentals of Testing (4). Revise those first, then practise explaining one or two of your own projects end to end, because most Cognizant interviewers ask you to walk through real work.
Are these the exact questions asked at Cognizant?
No. These are curated practice questions that match the skills and difficulty usually tested in it services interviews like Cognizant's. They are not a leaked or verified list of past questions.
Where does Cognizant hire ISTQB professionals in India?
Cognizant has large teams in Chennai, Bengaluru, Pune, Hyderabad, Kolkata. Openings and locations change often, so check the Cognizant careers page and filter by city and experience.