testing

name	testing
description	Guides ccusage Rust and Vitest tests. Use when adding or fixing cargo tests, CLI snapshots, Claude model pricing, LiteLLM compatibility, Vitest tests, or fixture-backed tests.

ccusage Testing

Use the tdd skill for logic changes, Red-Green-Refactor workflow, focused runner commands, Rust test syntax, and general test readability rules. This skill owns ccusage-specific Rust and Vitest test rules: fixtures, adapter coverage, pricing/model behavior, CLI output, schema artifacts, and package tooling.

Shared Rules

• Prefer behavior-focused tests over schema-shape tests unless schema normalization itself is the behavior.
• Avoid try/catch in tests for expected failures. Use native result, throwing, rejecting, or explicit failure assertions for the test framework.
• Avoid if branches inside test bodies. Split behaviors into separate tests or table-driven cases.
• Tests do not need to be DRY. Prefer repeated, explicit setup when duplication makes each behavior easier to read.
• Do not hoist one-off values out of tests when sharing them hides the behavior.
• Skipped local-data smoke tests are acceptable when real user log directories catch schema drift, but they must not fail on clean CI machines.

Rust Tests

For repo-wide validation, prefer the just recipe because it runs Vitest and Rust tests together:

direnv exec . just test

Put Rust unit tests near the module they exercise with #[cfg(test)] mod tests. When splitting a large module, move its tests with the code instead of leaving unrelated tests in main.rs.

Read references/rust.md for fixture-backed parser, path discovery, SQLite loading, dedupe, aggregation, pricing, CLI output parity, model, and readability rules. For focused cargo commands, Red-Green-Refactor examples, Rust test attributes, and syntax examples, read ../tdd/references/rust.md.

Vitest Tests

Read references/vitest.md for TypeScript package launcher, schema artifact, benchmark script, docs/package tooling, and fs-fixture test rules.