Why shouldn't I test mock behavior?

Testing mock behavior only verifies that your test setup is present; it doesn't prove that your actual application logic works, which leads to fragile tests.

Can this skill help with flaky tests?

Yes, by preventing incomplete mocks and ensuring you understand dependency side effects, it reduces the common causes of non-deterministic or 'mysterious' test failures.

What are the Iron Laws of testing?

The Iron Laws are: NEVER test mock behavior, NEVER add test-only methods to production classes, and NEVER mock without fully understanding dependencies.

How does this skill prevent production code pollution?

It identifies methods that are only used in test files and suggests moving them to external test utilities rather than letting them reside in production classes.

Testing Anti-Patterns Guard

Name: Testing Anti-Patterns Guard
Author: NickCrew

byNickCrew

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セキュリティとテスト

Identifies and prevents common testing mistakes like over-mocking and production code pollution to ensure high-quality, resilient test suites.

This skill acts as an automated architectural guardrail to ensure that tests verify real application behavior rather than implementation details or mock configurations. It enforces strict testing standards by identifying 'Iron Law' violations, such as asserting on the existence of mocks, polluting production classes with test-specific methods, and creating incomplete mocks that lead to false confidence. By integrating these best practices into the development workflow, the skill helps engineers maintain clean production code and build robust Test-Driven Development (TDD) habits.

主な機能

01Prevents assertions on mock existence to focus on real behavior

02Provides gate functions to validate mocking logic before implementation

037 GitHub stars

04Encourages TDD cycles to ensure tests fail for the right reasons

05Enforces full schema completeness for API and data mocks

06Identifies and blocks test-only methods in production classes

ユースケース

01Training developers on proper Test-Driven Development (TDD) patterns

02Reviewing and refactoring brittle test suites that rely on heavy mocking

03Enforcing clean code standards during the implementation of new features

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add nickcrew/claude-cortex testing-anti-patterns

For use in Claude.ai and ChatGPT

Download Skill