How do you achieve parallel test execution and why does it matter?
- parallel execution
- performance
- test infrastructure
Answer it first, then compare. Nothing here is saved or scored.
Model answer
Parallel execution reduces feedback time, a 60-minute suite can run in 10 minutes across 6 workers. Requirements: test isolation (no shared state or data), independent test environments or careful resource partitioning, and a runner that supports parallelism (Playwright shards, Selenium Grid, TestNG). Challenges: shared databases (use unique prefixes or separate schemas), file system conflicts, and port collisions. Monitor for flakiness introduced by parallelism.
What interviewers listen for
- Test architecture instinctsYou can defend why your suite is shaped like a pyramid, a trophy, or a honeycomb.
- Locator disciplineYou rank selector strategies by stability and explain when to break the rule.
- Flaky test ownershipYou debug to a structural fix instead of retry-until-green.
- Parallelisation literacyYou know how your framework isolates state, fixtures, and database access across workers.