langgraph-testing-evaluation

Use this file for high-level flow. Load references/ for detailed implementation.

| Validate node logic quickly | Unit tests with mocks | references/unit-testing-patterns.md | | Validate multi-step agent behavior | Trajectory evaluation | references/trajectory-evaluation.md | | Track quality over datasets over time | LangSmith evaluation | references/langsmith-evaluation.md |

| Compare old vs new agent versions | A/B comparison | references/ab-testing.md |

Use this skill when you need to test or evaluate LangGraph/LangChain agents: writing unit or integration tests, generating test scaffolds, mocking LLM/tool behavior, running trajectory evaluation (match or LLM-as-judge), running LangSmith dataset evaluations, and comparing two agent versions with A/B-style offline analysis. Use it for Python and JavaScript/TypeScript workflows, evaluator design, experiment setup, regression gates, and debugging flaky/incorrect evaluation results. Source: lubu-labs/langchain-agent-skills.