`src/engine/bare/tests.rs` — the engine's test suite

The in-file test module for the driver (~5,300 lines) — the crate’s behavioral constitution. Reading test names here is the fastest way to learn what the engine guarantees.

Coverage highlights (by test-name theme)

• The loop: turn sequencing, terminal behaviors, finalize on every path, resume round-trips.
• Compaction: threshold/emergency boundaries (exactly-at vs one-past), no-op vs compacted feeds, no-progress guard, deferred-turn reservation, zero-window policy.
• Dispatch: parallel wave planning, sibling discard, recovery ceiling (attempts == 6), panic isolation, unknown-tool pre-answering.
• Cancellation: every checkpoint (model call, stream, tool, backoff, pre-run).
• Config: setter idleness, temp-dir lifecycle, overhead caching.

Behavior notes

• Tests double as specification: names are behavior sentences (“a_zero_window_disables_the_window_policy”), and the project’s TESTING.md culture (fail-first, both-ways boundaries) is visible throughout.
• Cross-file integration tests (tests/) cover subsystem seams end-to-end — see examples & tests.

Deep dive: Testing.