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mediumAutomation Test Engineer interview question

You are asked to load test a new checkout API before a big sale. How do you plan and run it?

What the interviewer wants to hear

  • Agree goals: expected traffic, latency and error targets
  • Realistic scenarios and data based on production patterns
  • Production-like environment and monitoring
  • Ramp up, steady load, spike and soak as needed
  • Analyse percentiles and bottlenecks, report and retest

Model answer

I start by agreeing targets with the team: expected peak requests per second for the sale with some headroom, p95 latency targets and an acceptable error rate. I study production traffic to build realistic scenarios, like browse, add to cart and pay in the right ratios, with varied test data. I write the scripts in k6 or JMeter with thresholds so the run passes or fails clearly. The environment should be production-like in size and config, and third-party payment calls are stubbed so we do not overload partners. I watch application metrics, database and infrastructure dashboards during the run. I ramp up gradually, hold steady load, then try a spike and possibly a soak test. Afterward I report p95 and p99 latency, throughput, errors and the first bottleneck found, then retest after fixes.

Can you answer it under time pressure?

Take a timed medium round and get scored on every answer.

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