adding-tests

name	adding-tests
description	Load this skill when a project includes tests, and you are finishing things like bug fix or feature addition and you plan to do tests related work.

Adding Tests

Core Principle

One test is usually enough. Only add multiple tests if the bug manifests differently under multiple conditions.

Test behavior, not implementation. Validate outcomes, not code paths.

A test's value is measured by:

1. Does it fail when user-facing behavior breaks?
2. Does it stay green when internals are refactored?
3. Does it catch the real issue it was written for?

Routing

Identify your context, then read the corresponding file:

Context	When to use	Reference
Bug fix	Fixing a reported issue, adding a regression guard	branches/bug-fix.md
New feature	Adding new behavior, validating a spec	branches/new-feature.md

Universal Rules

These apply regardless of context:

• Prefer integration tests — they catch real bugs; unit tests rarely do for most projects
• Mock as little as possible — use real deps, temp dirs, test guards
• One behavior per test — don't combine multiple assertions for unrelated behaviors
• Test the public surface — never modify production code (add params, expose internals) to make a test work

Read the relevant branch file for context-specific guidance.