Tdd

Test-Driven Development (TDD)

The Iron Law

NO PRODUCTION CODE WITHOUT A FAILING TEST FIRST

Write code before the test? Delete it. Start over.

The Cycle

1. RED — Write a test that fails. Run it. Confirm it fails for the right reason.
2. GREEN — Write the minimum code to make the test pass. Nothing more.
3. REFACTOR — Clean up. Both test and production code. Tests must still pass.

In the Aixlarity Codebase

# Run a specific test
cargo test -p aixlarity-core test_name

# Run all tests
cargo test

# Run with output
cargo test -- --nocapture

What Counts as "Minimum Code"

• If the test expects a return value, hardcode it first. Then generalize.
• If the test expects an error, return the error. Do not add error handling for cases no test covers yet.
• Resist the urge to "finish" the function. Let the next test drive the next behavior.

When to Skip (Ask the User First)

• Throwaway prototypes that will be deleted within the session.
• Generated code (e.g., provider adapter boilerplate).
• Configuration files.