common-testing-k

Knowledge skill — Testing philosophy, coverage priorities, naming conventions, anti-patterns.

Testing Standards

Tests define behavior. Reading the test suite should tell you what the system does without reading the implementation.

Philosophy

• Test actual code paths, not mocked abstractions
• Minimize mocking — mock only external services at boundaries
• Tests should exercise the same code path production uses
• Tests that fail are valuable information — don't "fix" the test to match broken code

Coverage Priorities

1. Happy path — normal successful operation
2. Error cases — what happens when things fail
3. Edge cases — boundary conditions, empty inputs, large inputs
4. Integration — components working together

Structure and Naming

Given/When/Then structure. Names read as behavior descriptions:

• GOOD: "returns 401 when token is expired"
• BAD: "test_auth_middleware"

Anti-Patterns

Tests that lie — mocking the thing being tested, assertions that assert nothing, tests changed to match broken behavior.

Tests that waste — testing implementation details, testing that the language works, excessive mocking that disconnects from reality.

Tests that mislead — skipped tests with eternal TODOs, names that don't match what they test, failure messages that don't help debug.