Loading...
Loading...
Browse 5 real-world technical and behavioral interview questions about Test isolation. Review scenarios, edge cases, and architectural best practices.
Make every test create its own preconditions under a generated identity, scope each assertion to records that test owns, and treat cleanup as housekeeping rather than as the isolation mechanism, because teardown does not run when a test is killed.
Quarantine and measure before fixing: keep per-test pass history so you can rank offenders and restore a trustworthy signal, then work the root-cause families one at a time. Retries belong in a narrow, logged, budgeted policy, because a blanket rerun turns a real product race condition into a green build.
The failing test is a victim, not the cause: something earlier mutated state it shares, usually a module evaluated once, a global that was patched and not restored, or rows left in a database. Bisect the ordering to find the pair, then remove the sharing.
Give each thread its own WebDriver session held in thread-local storage, remove every other piece of shared mutable state including test data and static fields, size the run to the grid's slots so requests queue rather than time out, and quit every session even on abnormal exit.
Make it reproducible before you make it pass. Pin the ordering seed, then work through the sources of non-determinism the test is exposed to - wall-clock time, global random state, hash-dependent iteration, real network calls and shared resources - and inject each one so the test controls it.