Testing is where coding agents genuinely earn their keep, since a good test suite gives the agent a way to verify its own work rather than you having to catch every issue manually.
This is one of the most genuinely reliable use cases for coding agents today: generating test coverage for code whose intended behavior is already clear. The agent has a well-defined target to test against.
More advanced agent workflows run tests automatically after generating code, then use failures to inform the next revision, closer to how a human developer works iteratively. This loop is part of why multi-step multi-agent systems often assign a dedicated testing subagent.
An agent can write tests that pass while still missing genuinely important edge cases it didn’t think to consider, since it’s testing against its own understanding of the requirements. Existing test coverage for the surrounding code, and human review of what the generated tests actually check, remain necessary safeguards.
Coding agents strengthen their own reliability when they can run and act on real test results, but the tests they generate still need human review. See Terminal-Bench for coding-agent results.
