Curated interview practice questions with answers. These are practice scenarios, not a verified list of past interview questions.
About UST hiring for ISTQB roles
UST is a digital transformation and IT services company with large delivery centres in India, particularly in Kerala. It provides software development, testing, cloud, data and AI services for clients in healthcare, retail, banking and semiconductors. It hires in India for software engineers, test engineers, data engineers and analysts.
For ISTQB roles, this UST practice set focuses most on White-Box, Experience and Collaboration-Based Testing (6), Static Testing (6), Fundamentals of Testing (4), Managing the Test Activities (4). It has 18 easy, 11 medium, 1 hard questions, so you can start easy and work up to the harder ones.
Typical pattern based on public candidate experiences. Rounds vary by role, team and year.
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01
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.
02
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.
03
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.
04
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.
05
Which work products can be examined by static testing?
Almost any work product that can be read and understood: requirements, user stories, acceptance criteria, architecture and design documents, source code, test plans, test cases, test charters, backlog items, contracts, project plans, schedules and budgets. Static analysis tools need work products with a formal structure, such as code or models with defined syntax. Products that are hard for humans to interpret, like third-party executable code, are not suitable for review.
The exam has 40 multiple-choice questions, each worth one point. The duration is 60 minutes, and candidates taking it in a non-native language usually get 25 percent extra time, making 75 minutes. The pass mark is 65 percent, which means 26 correct answers. There is no negative marking. Questions are mapped to learning objectives at K1, K2 and K3 levels.
07
What are entry and exit criteria? How do they relate to Definition of Ready and Definition of Done?
Entry criteria define preconditions for starting an activity, such as available resources, testware, a stable build and a test environment. Exit criteria define what must be achieved to finish, such as coverage reached, unresolved defect counts, defect density and passed tests. Running out of time or budget can also be a valid exit. In Agile, exit criteria are often called the Definition of Done and entry criteria for a story the Definition of Ready.
08
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.
09
Payment type has 3 partitions (card, UPI, wallet) and customer type has 2 (new, existing). What is the minimum number of tests for Each Choice coverage?
Each Choice coverage needs every partition from each input used at least once, and one test can cover one partition of each input at the same time. So the minimum equals the largest number of partitions: 3. Example tests: card with new, UPI with existing, wallet with new. Covering all combinations would need 3 x 2 = 6 tests, which is not required for Each Choice.
10
Find the minimum tests for 100 percent statement and branch coverage of this code.
read(x)
if x > 10:
print('big')
print('done')
Statement coverage: one test with x = 15 executes every statement, so 1 test.
Branch coverage: the if has a true and a false outcome, so tests with x = 15 and x = 5 are needed, 2 tests.
11
Explain collaborative user story writing, the 3 Cs and INVEST.
User stories are written collaboratively by business, development and testing. The 3 Cs are Card (the medium describing the story), Conversation (how the story will be used, documented or verbal) and Confirmation (the acceptance criteria). A good story follows INVEST: Independent, Negotiable, Valuable, Estimable, Small and Testable. If stakeholders cannot say how to test a story, it is probably unclear or does not reflect real value.
12
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.
13
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.
14
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.
The test pyramid shows that tests have different granularity and that a healthy suite has many small, fast, isolated tests at the bottom, such as unit or component tests, and fewer large, slow, complex end-to-end tests at the top, such as UI tests. Middle layers often cover API or integration tests. The pyramid helps teams plan automation so the suite is fast, stable and cheap to maintain.
16
How do you report test status to non-technical stakeholders?
I focus on decisions they need to make. I use a short dashboard: overall status in plain words, coverage of key requirements, open critical defects and their business impact, top risks with mitigation, and what is needed from them. I avoid jargon, use simple charts and trends, and keep detailed data available for anyone who wants it. Different audiences may need different levels of detail.
17
Why does 100 percent branch coverage guarantee 100 percent statement coverage, but not the other way round?
Every statement lies on at least one branch, so exercising all branches executes all statements. The reverse fails when a decision has an empty outcome. Example: 'if x > 10: print(big)' followed by 'print(done)'. One test with x = 15 runs every statement, giving 100 percent statement coverage, but the false branch is never taken, so branch coverage is only 50 percent. This is called subsumption.
Static testing detects defects in the earliest phases, when they are cheapest to fix. It finds defects that dynamic testing cannot, such as unreachable code or defects in non-executable work products. It helps evaluate quality and build confidence, improves shared understanding among stakeholders, and gives fast feedback on code through static analysis in CI. Reviews cost effort, but the total cost of quality is usually lower.
19
What is static testing and how is it different from dynamic testing?
Static testing examines work products without executing them, through manual reviews or static analysis tools. Dynamic testing executes the software. Static testing finds defects directly, such as ambiguous requirements or coding standard violations, while dynamic testing causes failures whose defects are then located by debugging. Static testing works on non-executable products like requirements and test plans, and finds defects dynamic testing cannot, such as unreachable code.
20
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.
21
Are there prerequisites for CTFL, and does the certificate expire?
There are no formal prerequisites for the Foundation Level exam; students, freshers and experienced professionals can all take it, although some practical testing exposure makes the syllabus easier. The CTFL certificate has lifetime validity and does not need renewal. It is the prerequisite for ISTQB Advanced Level and most Specialist certifications, so it is the starting point of the ISTQB path.
Register through the ISTQB member board for India or an ISTQB-accredited exam provider. Create an account, choose CTFL v4.0, and pick either an online proctored exam or a test centre. For online exams, check your webcam, microphone and internet in advance, and keep a valid government photo ID ready. Results are usually shared soon after the exam, followed by the certificate.
23
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.
24
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.
25
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.
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.
27
What is the difference between 2-value and 3-value boundary value analysis?
BVA applies to ordered partitions. In 2-value BVA each boundary has two coverage items: the boundary value and its closest neighbour in the adjacent partition. In 3-value BVA there are three: the boundary and both neighbours. For a valid range 18 to 60, 2-value gives 17, 18, 60, 61, and 3-value gives 17, 18, 19, 59, 60, 61. 3-value is stricter and can catch defects like 'x == 18' written instead of 'x >= 18'.
28
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.
29
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.
30
Your defect tracker is full of duplicate defects from several testers. How do you fix this?
I would set up a short daily triage to merge duplicates and link them to one master defect. Testers should search existing defects by module and keywords before logging, and use clear titles in a standard format such as 'Module - action - result'. Defined components and labels make searching easier. Tracking duplicate rates also shows whether the guidance is working.
Tips to crack the UST ISTQB interview
Practise aptitude and coding questions for the assessment, focusing on accuracy within time limits.
Revise SQL, testing concepts and your main programming language, and prepare examples from your projects.
Learn about UST's history as UST Global and its large Thiruvananthapuram campus for company questions.
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; UST interviewers usually ask follow-ups on your first answer.
Frequently asked questions
How many rounds are there in the UST ISTQB interview?
Candidates usually go through 4 stages: Online assessment (aptitude + reasoning); Coding test; 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 UST ISTQB interview?
This practice set leans on White-Box, Experience and Collaboration-Based Testing (6), Static Testing (6), Fundamentals of Testing (4), Managing the Test Activities (4). Revise those first, then practise explaining one or two of your own projects end to end, because most UST interviewers ask you to walk through real work.
Are these the exact questions asked at UST?
No. These are curated practice questions that match the skills and difficulty usually tested in it services interviews like UST's. They are not a leaked or verified list of past questions.
Where does UST hire ISTQB professionals in India?
UST has large teams in Thiruvananthapuram, Kochi, Bengaluru, Chennai, Hyderabad. Openings and locations change often, so check the UST careers page and filter by city and experience.