FrontendHaltTesting·Intermediate·Coding·1 min read
What is a common cause of flaky tests around async code?
Short interview answer
Uncontrolled nondeterminism — real timers, real randomness, unmocked network variance, or race conditions between two async operations — makes outcomes depend on timing that differs between runs instead of being deterministic.
Key takeaway
Explain the underlying mental model clearly, then support it with a concrete example and its trade-offs.