How does the 'Gate Function' work?

Gate functions are checkpoints that trigger before common actions (like adding a mock or a new method). They require the user or AI to verify the action against best practices before proceeding.

How does this skill prevent production code pollution?

It identifies methods intended only for testing and forces their relocation to test-utility files, ensuring production classes remain focused on business logic and adhere to the YAGNI principle.

What are the core 'Iron Laws' this skill enforces?

The skill enforces three non-negotiable rules: never test mock behavior, never add test-only methods to production classes, and never mock without fully understanding dependencies.

Why shouldn't I test mock behavior?

Testing mock behavior only proves that your mock works, not your application. It leads to false confidence and brittle tests that pass even when the real component is broken.

Testing Anti-Patterns

Name: Testing Anti-Patterns
Author: dsifry

bydsifry

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Security & Testing

Enforces high-quality testing standards by identifying and preventing common pitfalls like mock-testing and production code pollution.

About

The Testing Anti-Patterns skill provides a rigorous framework for Claude to ensure the creation of maintainable, deterministic, and effective test suites. By adhering to the 'Iron Laws' of testing, it prevents developers and AI agents from making common mistakes such as asserting on mock existence instead of real behavior, polluting production classes with test-only methods, and creating incomplete mocks that lead to silent failures. This skill integrates gate functions into the development process, promoting a strict TDD cycle and ensuring that tests provide genuine confidence in code reliability before PR submission.

Key Features

Identifies and blocks test-only methods from leaking into production code
Enforces comprehensive dependency analysis before implementing mocks
29 GitHub stars
Ensures mock data structures completely mirror real API schemas
Provides automated 'Gate Functions' to validate test integrity
Prevents assertions on mock behavior versus real component logic

Use Cases

Refactoring brittle test suites to focus on real behavior instead of implementation details
Cleaning up production codebases by migrating test-specific logic to utility helpers
Enforcing strict Test-Driven Development (TDD) during the creation of new features

About

Key Features

Identifies and blocks test-only methods from leaking into production code
Enforces comprehensive dependency analysis before implementing mocks
29 GitHub stars
Ensures mock data structures completely mirror real API schemas
Provides automated 'Gate Functions' to validate test integrity
Prevents assertions on mock behavior versus real component logic

Use Cases

Refactoring brittle test suites to focus on real behavior instead of implementation details
Cleaning up production codebases by migrating test-specific logic to utility helpers
Enforcing strict Test-Driven Development (TDD) during the creation of new features