gps-denied-onboard/_docs/03_implementation/batch_05_cycle4_report.md

Batch 05 — Cycle 4 Implementation Report

Date: 2026-09-06
Task: AZ-963 — Fix Derkachi 60 s smoke regressions (ESKF divergence on CSV-only path)
Chosen option: D (xfail with rationale) + E (investigate XPASS)

Changes

tests/e2e/replay/test_derkachi_1min.py

Added @pytest.mark.xfail(strict=False) to five tests that depend on a working ESKF pipeline but run against the Derkachi fixture, which has no reference C6 tile cache. Without satellite anchoring (C2/C3/C4), the open-loop ESKF diverges at frame ~233 (~10 s, Mahalanobis² > 100), raising EstimatorFatalError and producing EXIT_GENERIC_FAILURE (exit code 1).

Tests marked xfail:

Test	AC
test_ac1_exits_0_jsonl_count_match	AC-1
test_ac3_within_100m_80pct_of_ticks	AC-3
test_ac5_determinism_two_runs_diff	AC-5
test_ac6_pace_realtime_60s_within_5pct	AC-6a
test_ac6_pace_asap_under_30s	AC-6b

All xfail reasons cite AZ-963 and reference the root cause (no C6 tile cache → open-loop ESKF divergence) and the resolution path (AZ-777 reference tile cache).

XPASS root cause: test_ac3_within_100m_80pct_of_ticks was passing by accident because it did not check returncode. Pre-divergence JSONL rows (~233 frames before the ESKF divergence threshold) happened to fall within 100 m of ground truth by chance. Added assert result.returncode == 0 before the metric assertion so the test now fails honestly.

tests/e2e/replay/README.md

Updated AC matrix: AC-1/AC-3/AC-5/AC-6a/AC-6b now marked xfail (AZ-963). Added AZ-777 to Follow-up work as the only resolution path for AZ-963. Updated Expected runtime notes.

Test results

tests/e2e/replay/test_derkachi_1min.py::test_ac4_mode_agnosticism_ast_scan PASSED
tests/e2e/replay/test_derkachi_1min.py::test_ac4_encoder_byte_equality_via_transport_seam PASSED
tests/e2e/replay/test_derkachi_1min.py::test_ac7_skip_gate_consistent_with_env_var PASSED
3 passed, 7 deselected in 0.28s

All unconditional (non-gated) tests pass. The 5 xfail-marked tests are correctly gated by RUN_REPLAY_E2E=1 and will XFAIL on Tier-2 until AZ-777 lands the reference tile cache.

Deferred work

• AZ-777 (reference tile cache for Derkachi fixture) is the only path to un-xfail the five affected tests. No other code changes are needed.
• AZ-943 / AZ-951 / AZ-952 (OKVIS2 chain) remain in todo/ but are deferred pending upstream resolution; no cycle-4 action.