Closes the spec §8 Ring 3 deferral. Two integration tests against
FOXHUNT_TEST_DATA real MBP-10 day files:
buy_and_hold_full_day
Walk the first .dbn.zst from open to close; submit a market buy
of 1 lot at the first event, run the full step-loop
(apply_snapshot + step_resting_orders) over every subsequent
event, then close with a market sell at the last event. Assert
realized P&L matches (close_mid - open_mid) within ±2 ticks per
spec slippage budget. Proves the book-walking + position
accounting + step-loop orchestration are wire-level correct
against real data, not just hand-crafted JSON fixtures.
walk_book_one_full_day
Same fixture, no trades — just iterates every event through
apply_snapshot + step_resting_orders and asserts the book
invariants (bid/ask monotonicity, no-crossed-book) hold at every
10_000-event checkpoint across the full day. Stress test of
the kernel against real market microstructure (gaps, locked
markets, regime shifts).
Both tests skip gracefully when FOXHUNT_TEST_DATA is absent OR the
predecoded sidecars are empty (the current 40-byte placeholder
fixtures in test_data/futures-baseline/ES.FUT/*.predecoded.bin will
trigger the skip path; populating those with a real Databento decode
makes both tests fire end-to-end). Ring 3 is operational, not
CI-mandatory.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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