Testing Strategy

Status: Current Last updated: 2026-05-12 21:14 EDT

Unit tests

Each command module includes #[cfg(test)] unit tests that verify counting logic, edge cases, and output formatting against known inputs.

cargo nextest run -p clan-core          # All tests (preferred)
cargo test -p clan-core                 # Alternative
cargo test --doc -p clan-core           # Doctests only (nextest can't run these)

Snapshot tests

Snapshot tests use insta to capture command output and detect regressions. They live alongside the test that produces them:

crates/clan/clan-core/tests/snapshots/ — snapshots from transform_golden.rs, converter_golden.rs, and other top-level tests in the tests/ directory
crates/clan/clan-core/tests/clan_golden/snapshots/ — snapshots produced by the clan_golden test module (paired @clan/@rust pairs)

cargo insta review -p clan-core         # Review pending snapshot changes
cargo insta accept --all                    # Accept all pending changes

When you change a command’s output format, the snapshot test will fail. Review the diff to confirm the change is intentional, then accept.

Golden tests

Golden tests compare our output against legacy CLAN C binaries. See Golden Tests for details.

Running specific tests

# By name pattern
cargo nextest run -p clan-core -E 'test(freq)'

# Only golden tests
cargo nextest run -p clan-core -E 'test(golden)'

# Only indent tests
cargo nextest run -p clan-core -E 'test(indent)'

Test fixtures are real CHAT files from the reference corpus at resources/corpus/reference/ (at the repo root). Never create ad hoc .cha test files — use existing corpus files or ask for new ones to be added to the reference corpus.

Current test counts

The clan-core suite spans unit, snapshot, golden, and integration tests. The absolute count moves as commands are added or extended; get the live number with:

cargo nextest list -p clan-core

The last line of the summary is the total count.

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