Night Market Skill — ported from claude-night-market/parseltongue. For the full experience with agents, hooks, and commands, install the Claude Code plugin.

Python Testing Hub

Testing standards for pytest configuration, fixture management, and TDD implementation.

Table of Contents

1. Quick Start
2. When to Use
3. Modules

Quick Start

1. Dependencies:

   pip install pytest pytest-cov pytest-asyncio pytest-mock

2. Configuration: Add the following to

   pyproject.toml

   :

   [tool.pytest.ini_options]
   testpaths = ["tests"]
   addopts = "--cov=src"
   

3. Verification: Run

   pytest

   to confirm discovery of files matching

   test_*.py

   .

When To Use

• Constructing unit and integration tests for Python 3.9+ projects.
• Isolating external dependencies using

  pytest-mock

  or custom monkeypatching.
• Validating asynchronous logic with

  pytest-asyncio

  markers and event loop management.
• Configuring project-wide coverage thresholds and reporting.

When NOT To Use

• Evaluating test quality - use pensive:test-review instead
• Infrastructure test config - use leyline:pytest-config
• Evaluating test quality - use pensive:test-review instead
• Infrastructure test config - use leyline:pytest-config

Modules

This skill uses modular loading to manage the system prompt budget.

Core Implementation

• See

  modules/unit-testing.md

  - AAA (Arrange-Act-Assert) pattern, basic test structure, and exception validation.
• See

  modules/fixtures-and-mocking.md

  - Request-scoped fixtures, parameterization, and boundary mocking.
• See

  modules/async-testing.md

  - Coroutine testing, async fixtures, and concurrency validation.

Infrastructure & Workflow

• See

  modules/test-infrastructure.md

  - Directory standards,

  conftest.py

  management, and coverage tools.
• See

  modules/testing-workflows.md

  - Local execution patterns and GitHub Actions integration.

Standards

• See

  modules/test-quality.md

  - Identification of common anti-patterns like broad exception catching or shared state between tests.

Exit Criteria

• Tests implement the AAA pattern.
• Coverage reaches the 80% project minimum.
• Individual tests are independent and do not rely on execution order.
• Fixtures are scoped appropriately (function, class, or session) to prevent side effects.
• Mocking is restricted to external system boundaries.

Troubleshooting

• Test Discovery: Verify filenames match the

  test_*.py

  pattern. Use

  pytest --collect-only

  to debug discovery paths.
• Import Errors: Ensure the local source directory is in the path, typically by installing in editable mode with

  pip install -e .

  .
• Async Failures: Confirm that

  pytest-asyncio

  is installed and that async tests use the

  @pytest.mark.asyncio

  decorator or corresponding auto-mode configuration.