View failed test assertions for performance tests

The Tests tab in your performance test results shows how your test assertions behave as load increases. It uses the same pm.test() assertions defined in your collection and runs them during the performance test, without additional configuration.

During a performance test, Postman runs your collection under load, running your assertions repeatedly as the number of virtual users increases. The Tests tab enables you to evaluate whether your API continues to behave under load.

Use the Tests tab to identify issues such as:

• Logic or data mismatches (for example, inventory going negative under load).
• Timeouts when services are overwhelmed.
• Race conditions caused by requests running at the same time, leading to inconsistent results.
• Workflow breakages due to caching or delayed consistency.

Analyze when failures occur

Use the Failure Trend view to understand when test assertion failures occur during the test run. This view enables you to identify when failures begin and how they relate to changes in load over time.

Learn more about viewing test assertion failure trends.

Analyze failures by load

Use the Tests vs VU view to understand how test assertions behave at different levels of virtual user load. This view enables you to identify at what point your system begins to break and which assertions fail as load increases.

Learn more about viewing test assertions by virtual user load.