The default Rust gate is the bounded unit suite:

cargo nextest run --profile default --lib

CI uses the non-fail-fast profile so one run reports the full failure set:

cargo nextest run --profile ci --lib

For local edit loops, use the quick profile with the module or test filter you are changing:

cargo nextest run --profile quick --lib <filter>

The profile timeouts are guardrails for hangs, not performance targets. When doing test-suite speed work, capture before/after wall time and the slowest tests from the nextest summary so lock contention and fixture setup costs stay visible.

Full-pipeline audit/refactor regressions that intentionally run broad audit machinery live in the explicit slow tier:

cargo test --lib --features slow-tests code_audit
cargo test --lib --features slow-tests collect_refactor_sources_audit_write_uses_audit_refactor_engine

Use the slow tier when changing audit detector orchestration, audit fixability planning, or audit-driven refactor planning. These tests remain runnable, but they are not part of the default unit gate because they scan real fixture/checkouts and dominated local suite wall-clock time.

Hermetic CLI Fixtures

Ordinary Rust tests must use homeboy::test_support::HermeticTestContext for Homeboy subprocesses. It supplies owned HOME, config, data, artifact, runtime, temporary, daemon, and runner locations, and requires an explicit binary choice: TestBinary::HomeboyFixture for Cargo’s fixture binary or TestBinary::CurrentTest for the running test executable. This prevents tests from reading operator configuration or resolving an installed homeboy through PATH.

Host integration tests are opt-in: place them behind an explicit Cargo feature or an explicit command-line opt-in and document the required host service, credentials, and cleanup contract beside the test. They may use host state only when that contract is the behavior under test; they are excluded from the ordinary Rust gate.