| 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.
