Testing Standards

Coverage

• Every module gets tests — no untested code ships
• Test file naming follows the project's convention (e.g., test_*.py, *.test.ts, *_test.go)

Assertions

• Assert outcomes, not implementation details
• Test what the code does, not how it does it
• If an internal refactor breaks your tests, the tests were testing the wrong thing

Determinism

• Tests must be deterministic — no self-generated random test data
• Provide fixed test data; never have the test generate its own inputs randomly
• Flaky tests are bugs — diagnose the root cause, don't retry and hope

Fixtures

• No binary fixtures checked into the repo
• Build test data programmatically in test setup/fixtures
• For binary files that can't be built programmatically, download them from a URL during test setup

Independence

• Each test must run independently — no shared mutable state between tests
• Test order must not matter
• Clean up after yourself: temporary files, database state, mock patches