Testing Patterns Agent Skill

by langchain-ai

Unit testing and integration testing best practices

446 tokens

context cost

the whole folder, loaded on every use

files

instructions only

copies elsewhere

how many repositories repackaged it

111

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/langchain-ai/skills-benchmarks --skill testing-patterns

The instruction itself

6 sections, as written by the author

Testing Patterns

Write effective, maintainable tests using modern patterns.

Test Structure (AAA Pattern)

def test_user_registration():
    # Arrange
    user_data = {"email": "[email protected]", "password": "secure123"}

    # Act
    result = register_user(user_data)

    # Assert
    assert result.success is True
    assert result.user.email == "[email protected]"

Mocking External Services

from unittest.mock import Mock, patch

@patch('services.email.send_email')
def test_sends_welcome_email(mock_send):
    mock_send.return_value = True

    register_user({"email": "[email protected]"})

    mock_send.assert_called_once_with(
        to="[email protected]",
        template="welcome"
    )

Fixtures and Factories

import pytest
from factories import UserFactory

@pytest.fixture
def user():
    return UserFactory.create(role="admin")

@pytest.fixture
def authenticated_client(user):
    client = TestClient(app)
    client.login(user)
    return client

def test_admin_dashboard(authenticated_client):
    response = authenticated_client.get("/admin")
    assert response.status_code == 200

Integration Tests

@pytest.mark.integration
def test_full_checkout_flow(db_session, stripe_mock):
    # Create test data
    user = create_user()
    product = create_product(price=100)

    # Execute flow
    cart = add_to_cart(user, product)
    order = checkout(cart, payment_method="card")

    # Verify
    assert order.status == "completed"
    assert stripe_mock.charges.create.called

Test Coverage Goals

Unit tests: 80%+ coverage
Integration tests: Critical paths
E2E tests: Happy paths only

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How to use it

Copy the folder

Take langchain-ai/testing-patterns from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

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