Why SDET Interviews Still Ask Coding Questions in the Age of AI (And How to Prepare)
A lot of time I have wondered why basic programs are being asked in interviews for SDET when AI is here. The answer is not about memorizing solutions. It is about demonstrating how you think through problems step by step.
Problem solving and logic building is what we learn. When we understand how to solve such problems, it is not about the correct solution — it is about creating steps to reach it.
What Coding Questions Actually Test
- Problem decomposition — can you break a complex scenario into testable steps?
- Debugging instinct — can you trace through logic to find where it breaks?
- Communication — can you explain your approach while coding?
- Edge case awareness — do you instinctively think about null inputs, empty arrays, and boundary values?
The Data Structures That Matter for SDETs
- HashMap/Dictionary — test data management, response validation, configuration
- Lists/Arrays — assertion collections, test parameterization
- Sets — deduplication in test data, unique validation
- Queues — event-based testing, message queue validation
- Trees — DOM traversal, page object hierarchies
15 SDET Coding Interview Questions with QA Context
- Validate that an API response contains all required fields (HashMap traversal)
- Find duplicate test case names in a test suite (Set operations)
- Sort test results by execution time (Sorting algorithms)
- Parse a CSV test data file and validate each row (String manipulation)
- Implement a retry mechanism with exponential backoff (Recursion)
- Compare two JSON responses and find differences (Tree comparison)
- Group test failures by error type (HashMap grouping)
- Validate that a URL follows the correct format (Regex/String)
- Implement a simple test result aggregator (Reduce/Accumulator)
- Find the longest common prefix in a set of test names (String matching)
- Validate balanced brackets in a test expression (Stack)
- Merge two sorted test execution reports (Merge algorithm)
- Implement a simple rate limiter for API tests (Queue + timing)
- Parse nested JSON and extract specific values (Recursion)
- Design a simple test scheduler that handles dependencies (Graph/topological sort)
