Analog Devices India SDET Interview: Rounds, Questions and Preparation

What the job involves

An SDET (Software Development Engineer in Test) builds and maintains the automated test frameworks, tools, and CI pipelines that validate software, rather than only running manual test cases. In global semiconductor and embedded-product companies, the work often spans firmware, device drivers, host-side GUI/CLI tools, and data-acquisition or signal-processing software, so you write code in Python, C#, or C++ to test code. Day to day you read specs, design test cases, automate them, analyse failures, and report defects alongside developers and hardware teams.

Role and Technical Knowledge

1. 1

   What is the difference between a manual tester, an automation tester, and an SDET?

   Explain that an SDET writes production-quality code for test frameworks and tooling, owns CI integration, and can review developer code, not just execute scripts.

2. 2

   How would you design test cases for a feature that reads sensor data and displays it in a desktop application?

   Cover boundary values, invalid inputs, sampling-rate changes, disconnection handling, data accuracy against a reference, UI refresh, and logging or export checks.

3. 3

   What is the difference between a stub and a mock, and when would you use each in testing firmware or a hardware-dependent module?

   State that a stub returns canned data while a mock verifies interactions; use stubs to simulate a sensor and mocks to check that a driver calls the right register write.

4. 4

   Explain the test pyramid and where automation fits for an embedded or instrument-control product.

   Describe many fast unit tests, fewer integration tests, and few slow end-to-end hardware-in-the-loop tests, and note that hardware tests are expensive so they are kept minimal and stable.

Practical Scenarios and Coding

1. 5

   Write a Python function to check whether a list of measured voltages stays within a tolerance band, and list the test cases you would write for it.

   Show clean code with clear parameter names, then list empty input, single value, exact boundary, just outside boundary, and negative or NaN values.

2. 6

   A Selenium test passes on your machine but fails in the CI pipeline. How do you debug it?

   Check environment and browser versions, headless mode, timing and explicit waits, screen resolution, test data, and CI logs or screenshots before blaming the application.

3. 7

   How would you test a REST API that returns measurement data in JSON, including error handling?

   Cover status codes, schema and field validation, pagination, authentication, malformed requests, timeouts, and verifying the database or device state after the call.

4. 8

   You find a defect that only appears after running a test 100 times. How do you investigate and report it?

   Talk about reproducing reliably, capturing logs and timestamps, checking for race conditions or resource leaks, minimising the reproduction, and filing a clear report with severity and evidence.

Behavioural and HR

1. 9

   Tell me about a project where you automated a repetitive task. What was the outcome?

   Use the STAR format, quantify the time saved or errors reduced, and mention the tools you chose and why.

2. 10

   Describe a time you disagreed with a teammate about a technical decision. How did you handle it?

   Show that you listened, used data or a small experiment to settle the disagreement, and kept the relationship and the project goal first.

3. 11

   Why do you want to work as an SDET in a product-based hardware and software company rather than a services company?

   Connect your interest in coding, systems, and hardware-software interaction to long-term ownership of a product, and mention learning from senior engineers.

4. 12

   Are you comfortable relocating to the company's development centre, and what are your salary expectations as a fresher?

   Be honest and flexible on location, show awareness of typical fresher bands in the industry, and state that learning and growth matter more than a precise number at this stage.

Testing Fundamentals and Process

1. 13

   What is the difference between verification and validation, and give an example from an instrument or device product.

   Verification checks that the product is built correctly against spec, such as a register write test; validation checks the right product was built, such as confirming a measurement matches a calibrated reference.

2. 14

   Explain severity versus priority with an example relevant to a measurement tool.

   Severity is technical impact and priority is business urgency; a wrong reading on a rarely used range may be high severity but low priority, while a cosmetic issue on the main screen may be low severity but high priority.

3. 15

   What is regression testing, and how do you decide which tests to add to a regression suite?

   Define regression testing as re-checking that changes did not break existing behaviour, and say you include stable, high-value, frequently run tests and drop flaky or redundant ones.

4. 16

   What contents should a good bug report have, and why does a developer care about each field?

   List title, environment, build or firmware version, steps to reproduce, expected versus actual result, logs or screenshots, severity, and assignee, and explain how each reduces back-and-forth.