Curated interview practice questions with answers. These are practice scenarios, not a verified list of past interview questions.
About NTT DATA hiring for ISTQB roles
NTT DATA is a global IT services company and part of the NTT Group of Japan. It provides consulting, application services, cloud, infrastructure, data and testing services for clients in many industries. Its India delivery centres hire for software engineers, test engineers, data engineers, data analysts and infrastructure professionals.
For ISTQB roles, this NTT DATA practice set focuses most on Fundamentals of Testing (7), Testing Throughout the SDLC (5), Defect and Configuration Management (5), Static Testing (4). It has 18 easy, 10 medium, 2 hard questions, so you can start easy and work up to the harder ones.
Company type
IT services
Headquarters
Tokyo, Japan
Main India offices
Bengaluru, Pune, Noida, Hyderabad, Chennai
NTT DATA ISTQB interview process
Online assessment (aptitude + technical)
Technical interview
Managerial round
HR round
Typical pattern based on public candidate experiences. Rounds vary by role, team and year.
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01
Discounts depend on several combined business rules such as membership, coupon and festival offers. Which technique do you choose?
Decision table testing fits best, because the outcome depends on combinations of conditions. I would list the conditions and actions, build the full table, remove infeasible combinations, minimise columns where a condition does not matter, and turn each column into a test case. The table also exposes gaps or contradictions in the rules, which I would raise with the business analyst before testing.
In sequential models like waterfall and the V-model, testers join early for reviews and planning, but dynamic testing happens later once code exists. In iterative and incremental models such as Scrum, every iteration delivers a working increment, so static and dynamic testing happen at all levels in each iteration, regression testing is critical and automation is usually needed. The model affects scope, timing, documentation, techniques and automation.
03
The requirements say the system must be 'fast' and 'user-friendly'. What do you do?
I would log these as anomalies in a review because they are not testable. I would ask stakeholders for measurable criteria, for example 'search results appear within 2 seconds for 95 percent of requests at 1,000 concurrent users' and 'a new user completes registration in under three minutes without help'. Testable requirements make test design, acceptance and sign-off objective and prevent disputes later.
04
A test checks that the loan module correctly sends customer data to an external credit bureau API. Which test level is this?
This is system integration testing, because it tests the interface between our system and an external system, the credit bureau API. If it checked the interface between two internal modules of our own application, it would be component integration testing. In exam questions, keywords such as 'external system', 'third-party service' or 'other systems' point to system integration testing.
05
Your manual regression suite has not found a new defect for several releases. What do you do?
This points to the 'tests wear out' principle. I would review the suite against recent changes and defect data, refresh test data and steps, add tests for new features and risky areas, and run exploratory sessions to find new kinds of defects. Stable regression checks are still worth keeping and automating, because their job is to confirm unchanged areas still work, not to discover new defects.
06
What is risk, and how do project risks differ from product risks?
A risk is a potential event or condition whose occurrence causes an adverse effect. Risk level is determined by likelihood and impact. Project risks affect the management and control of the project, such as staff shortages, delays, budget cuts, vendor problems or tool issues. Product risks relate to quality characteristics of the product, such as missing functionality, wrong calculations, slow response, poor security or bad usability.
07
How does a tester contribute to release and iteration planning?
In release planning, testers help write testable user stories and acceptance criteria, take part in product and quality risk analyses, estimate test effort for stories, define the test approach and plan release testing. In iteration planning, they join detailed risk analysis of stories, check testability, break stories into testing tasks, estimate testing effort and identify the functional and non-functional aspects to test.
08
What are the typical objectives of testing according to the ISTQB CTFL v4.0 syllabus?
Testing objectives include evaluating work products such as requirements and code, triggering failures and finding defects, ensuring required coverage of the test object, reducing the risk of poor quality, verifying that specified requirements are met, checking compliance with contracts or regulations, giving stakeholders information for decisions, building confidence in quality, and validating that the test object works as users expect. Objectives vary with context, test level and the SDLC model.
09
Tell me about a time you missed a defect. What did you learn?
Situation: a defect in date formatting reached production after my testing. Task: understand why and prevent it. Action: I owned the miss, found my test data used only one locale, and added test cases for other date formats and locales. I also shared a checklist for locale testing. Result: no similar defect appeared in later releases, and I learned to review my test data as carefully as my test steps.
10
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.
11
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.
12
Tell me about a time you found an important defect. How did you report it?
Situation: while testing our final-year e-commerce project, I found checkout accepted expired coupon codes. Task: report it clearly before the demo. Action: I reproduced it three times and logged clear steps, expected and actual results, screenshots and the coupon data, and marked severity high because it meant revenue loss. Result: the developer fixed it within a day, and I added a regression test for coupon expiry.
13
Match these tasks to test activities: identifying test conditions, creating test data and suites, comparing actual and expected results, archiving testware.
Identifying and prioritising test conditions is test analysis. Creating test data, arranging test procedures and assembling test suites is test implementation. Running tests and comparing actual with expected results is test execution. Archiving testware, handing it over and recording lessons learned is test completion. Exams often mix design and implementation: designing test cases is test design, while preparing them to run is implementation.
14
Ten automated tests fail overnight, but the cause is an expired SSL certificate in the test environment. How should this be reported?
These failures are caused by the environment, not the test object, so they should not be logged as product defects. I would raise one environment issue with the infrastructure team, mark the test results as blocked or environment failure, and re-run after the certificate is renewed. I would also suggest monitoring certificate expiry so the same false positives do not recur.
15
Name the main test activities in the ISTQB test process.
The test process has seven activity groups: test planning, test monitoring and control, test analysis, test design, test implementation, test execution and test completion. They are often iterative or done in parallel rather than strictly sequential. How they are carried out depends on context, such as the SDLC, product risks, budget, time, team skills and regulations, so an Agile team performs them in small loops in every iteration.
16
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.
17
How does acceptance test-driven development (ATDD) work?
ATDD is a test-first approach. The team, including business, developers and testers, analyses the story and acceptance criteria in a specification workshop, then writes test cases before implementation. Positive tests come first, then negative tests and non-functional characteristics. Tests are written in a form stakeholders understand, cover every criterion without going beyond the story, and are often automated so they become executable requirements.
18
What certification path can you follow after CTFL?
After CTFL you can take Advanced Level modules: Test Analyst, Technical Test Analyst and Test Management. Specialist modules include Test Automation Engineering, Performance Testing, Security Testing, Mobile Application Testing, Usability Testing and AI Testing, among others. Expert Level certifications follow for experienced professionals. Choose based on your role: automation engineers pick technical paths, while leads pick test management.
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.
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.
21
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.
22
What is the difference between severity and priority?
Severity is the degree of impact the defect has on the system or its stakeholders, such as a crash or data loss. Priority is the urgency of fixing it, usually set by the business or product owner. Testers usually suggest severity, and priority is decided in triage. Example: a crash in a rarely used admin report is high severity but may be low priority.
23
What is the difference between confirmation testing and regression testing?
Confirmation testing checks that an original defect has been fixed, by re-running the failed tests or new tests that cover the change. Regression testing checks that a change, including a fix, has not caused adverse effects elsewhere, in the same component, connected components or the environment. Regression suites grow and run often, so they are strong candidates for automation, typically inside a CI pipeline.
24
What does a test plan contain according to CTFL v4.0?
A test plan typically covers: context of testing (scope, objectives, constraints, test basis); assumptions and constraints; stakeholders with roles and responsibilities; communication; a risk register of product and project risks; the test approach (test levels, types, techniques, deliverables, entry and exit criteria, independence, metrics, test data and environments); and budget and schedule. It documents how test objectives will be met and is updated as the project changes.
A defect report gives the people responsible for handling and resolving the defect enough information to fix it. It also provides a way to track the quality of the work product, and it offers ideas for improving the development and test processes. A good report is clear, reproducible and neutral in tone, so that developers can act on it quickly and managers can analyse trends.
26
Tell me about an exploratory testing session that found a critical defect.
Situation: a ticket booking app had passed all scripted tests. Task: run a one-hour exploratory session on seat selection. Action: I tried quick double taps, switching networks and booking the same seat from two devices. Result: two users could book the same seat. I logged a detailed report with videos, it was fixed before release, and concurrency tests were added to the regression suite.
27
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.
28
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.
29
A quantity field accepts 1 to 100. List the 2-value BVA test values.
The valid partition is 1 to 100, with invalid partitions below and above it. For each boundary, take the boundary and its closest neighbour in the adjacent partition. Lower boundary: 0 and 1. Upper boundary: 100 and 101. So 2-value BVA needs four values: 0, 1, 100 and 101, and four test cases give 100 percent 2-value boundary coverage.
30
Show two defects a static analysis tool can find without running the code.
def get_discount(amount):
if amount > 1000:
rate = 0.1
return amount * rate # rate undefined when amount <= 1000
def old_helper():
return 0
print('done') # unreachable code
The tool flags a possibly undefined variable, a data flow anomaly, and unreachable code. Both are found statically, before any test is executed.
Tips to crack the NTT DATA ISTQB interview
Revise SQL, testing and programming fundamentals for both the online assessment and technical interview.
Learn about NTT DATA's Japanese parent and its global integration of companies such as Dimension Data.
Be ready to discuss working with clients across time zones, as many teams support global accounts.
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; NTT DATA interviewers usually ask follow-ups on your first answer.
Frequently asked questions
How many rounds are there in the NTT DATA ISTQB interview?
Candidates usually go through 4 stages: Online assessment (aptitude + technical); Technical interview; Managerial round; 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 NTT DATA ISTQB interview?
This practice set leans on Fundamentals of Testing (7), Testing Throughout the SDLC (5), Defect and Configuration Management (5), Static Testing (4). Revise those first, then practise explaining one or two of your own projects end to end, because most NTT DATA interviewers ask you to walk through real work.
Are these the exact questions asked at NTT DATA?
No. These are curated practice questions that match the skills and difficulty usually tested in it services interviews like NTT DATA's. They are not a leaked or verified list of past questions.
Where does NTT DATA hire ISTQB professionals in India?
NTT DATA has large teams in Bengaluru, Pune, Noida, Hyderabad, Chennai. Openings and locations change often, so check the NTT DATA careers page and filter by city and experience.