Topic
Testing AI Agents & Tool Calling
13 posts on testing ai agents & tool calling — part of developer tools on the n4n AI blog.
What to unit test in a ReAct-style agent loop
A practical guide to unit testing ReAct agent loops: which components to mock, what assertions matter, and how to avoid flaky nondeterministic tests.
Unit tests vs integration tests for AI agents
A practitioner's head-to-head comparison of unit tests vs integration tests for AI agents across cost, latency, ergonomics, and where each fits in CI.
Unit testing LLM agents: a practical guide
A practical, ordered guide to unit testing LLM agents: isolate model calls, mock providers, assert on tool use, and test failure paths without flaky tests.
Testing multi-step tool calling with Claude Opus 4.5
A hands-on tutorial for testing multi-step tool calling with Claude Opus 4.5: build a deterministic eval harness, mock tools, and assert agent trajectories.
Testing Gemini 3 function calling against a JSON schema
A hands-on tutorial for testing Gemini 3 function calling against a JSON schema: build a validation harness, write pytest tests, and catch schema drift.
Testing function calling schemas for errors
Practical guide to testing function calling schemas for errors: validate JSON Schema locally, mock tool calls, and run cross-provider checks in CI.
Simulating flaky tool APIs when testing agent retries
Learn how to build a local flaky tool API simulator to exercise agent retry logic with controlled failures, latency, and chaos for reliable tests.
Mocking the n4n API in your agent test suite
Learn how to mock the n4n API for agent tests using pytest and respx, simulating tool calls, streaming, and provider fallback to ship reliable LLM agents.
How to test whether an agent picked the right tool
A practical guide to testing tool selection accuracy in LLM agents using deterministic eval harnesses, mocked tools, and assertion-based checks.
How to mock tool calls when testing GPT-5 agents
Learn practical techniques for mocking tool calls in GPT-5 agent tests so you can unit test agent logic without hitting live APIs or external services.
Deterministic testing for non-deterministic agent loops
Practical strategies for building deterministic tests for LLM agent loops despite model non-determinism, with mocking, replay, and contract tests.
Catching hallucinated tool arguments before production
A practical how-to for detecting hallucinated tool call arguments in LLM agents before deployment, using schema validation and replay testing.
A test harness for agents that call multiple tools per turn
Build a test harness for multi-tool agent turns: script LLM responses, fake tools, assert call ordering, and inject failures to validate agent resilience.
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