[AZ-595] Batch 75: sitl_observer FDR-replay + scenario probe cleanup

Implement all 11 `sitl_observer` public surfaces as an offline
FDR-replay strategy (reads JSON fixtures under `${E2E_SITL_REPLAY_DIR}`
instead of live pymavlink/yamspy). Replace 12 per-scenario
`_harness_helpers_implemented` probes with one shared session-scoped
`sitl_replay_ready` fixture in `e2e/tests/conftest.py`.

Net: -636 LoC of duplicated scenario gating, +17 LoC shared fixture,
+38 new unit tests (596 total, up from 558). Includes K=3 cumulative
review for batches 73-75 (PASS).

Co-authored-by: Cursor <cursoragent@cursor.com>

e2e/tests/negative/test_ft_n_01_outlier_tolerance.py

@@ -22,40 +22,6 @@ from fixtures.injectors.outlier import OutlierInjectionReport
 from runner.helpers import outlier_tolerance_evaluator as ote
 
 
-@pytest.fixture(scope="module")
-def _harness_helpers_implemented() -> bool:
-    from runner.helpers import fdr_reader, imu_replay
-    from runner.helpers.frame_source_replay import FrameSourceReplayer
-
-    try:
-        replayer = FrameSourceReplayer(sink=_NullSink())  # type: ignore[arg-type]
-        try:
-            replayer.replay_video(Path("/tmp/non-existent.mp4"))
-        except NotImplementedError:
-            return False
-        try:
-            list(fdr_reader.iter_records(Path("/tmp/non-existent")))
-        except NotImplementedError:
-            return False
-        try:
-            imu_replay.ImuReplayer(emitter=_NullImuEmitter()).replay(Path("/tmp/non-existent.csv"))  # type: ignore[arg-type]
-        except NotImplementedError:
-            return False
-        return True
-    except Exception:
-        return False
-
-
-class _NullSink:
-    def write_frame(self, jpeg_bytes: bytes, timestamp_ms: int) -> None:
-        return None
-
-
-class _NullImuEmitter:
-    def emit(self, sample: object) -> None:
-        return None
-
-
 @pytest.mark.parametrize(
     "outlier_injection_derkachi",
     [{"density": "medium", "seed": 0}],
@@ -69,14 +35,13 @@ def test_ft_n_01_outlier_tolerance(
     evidence_dir,  # type: ignore[no-untyped-def]
     run_id: str,
     nfr_recorder,  # type: ignore[no-untyped-def]
-    _harness_helpers_implemented: bool,
+    sitl_replay_ready: bool,
 ) -> None:
-    if not _harness_helpers_implemented:
+    if not sitl_replay_ready:
         pytest.skip(
-            "FT-N-01 full replay requires runner.helpers.{frame_source_replay,"
-            "fdr_reader,imu_replay} — currently AZ-441 / AZ-407 leftovers. "
-            "AC-1/AC-2/AC-3 helper logic covered by "
-            "e2e/_unit_tests/helpers/test_outlier_tolerance_evaluator.py."
+            "FT-N-01 full replay requires `E2E_SITL_REPLAY_DIR` to point at a "
+            "prepared SITL replay fixture (AZ-595). AC-1/AC-2/AC-3 helper logic "
+            "covered by e2e/_unit_tests/helpers/test_outlier_tolerance_evaluator.py."
         )
 
     from runner.helpers import fdr_reader

e2e/tests/negative/test_ft_n_02_sharp_turn_failure.py

@@ -35,40 +35,6 @@ DERKACHI_IMU_CSV = DERKACHI_DIR / "data_imu.csv"
 DERKACHI_MP4 = DERKACHI_DIR / "flight_derkachi.mp4"
 
 
-@pytest.fixture(scope="module")
-def _harness_helpers_implemented() -> bool:
-    from runner.helpers import fdr_reader, imu_replay
-    from runner.helpers.frame_source_replay import FrameSourceReplayer
-
-    try:
-        replayer = FrameSourceReplayer(sink=_NullSink())  # type: ignore[arg-type]
-        try:
-            replayer.replay_video(Path("/tmp/non-existent.mp4"))
-        except NotImplementedError:
-            return False
-        try:
-            list(fdr_reader.iter_records(Path("/tmp/non-existent")))
-        except NotImplementedError:
-            return False
-        try:
-            imu_replay.ImuReplayer(emitter=_NullImuEmitter()).replay(Path("/tmp/non-existent.csv"))  # type: ignore[arg-type]
-        except NotImplementedError:
-            return False
-        return True
-    except Exception:
-        return False
-
-
-class _NullSink:
-    def write_frame(self, jpeg_bytes: bytes, timestamp_ms: int) -> None:
-        return None
-
-
-class _NullImuEmitter:
-    def emit(self, sample: object) -> None:
-        return None
-
-
 @pytest.mark.traces_to("AC-3.2,AC-1,AC-2,AC-3,AC-7")
 def test_ft_n_02_sharp_turn_failure(
     fc_adapter: str,
@@ -76,14 +42,13 @@ def test_ft_n_02_sharp_turn_failure(
     evidence_dir,  # type: ignore[no-untyped-def]
     run_id: str,
     nfr_recorder,  # type: ignore[no-untyped-def]
-    _harness_helpers_implemented: bool,
+    sitl_replay_ready: bool,
 ) -> None:
-    if not _harness_helpers_implemented:
+    if not sitl_replay_ready:
         pytest.skip(
-            "FT-N-02 full replay requires runner.helpers.{frame_source_replay,"
-            "imu_replay,fdr_reader} — currently AZ-441 / AZ-407 leftovers. "
-            "AC-2/AC-3 helper logic covered by "
-            "e2e/_unit_tests/helpers/test_sharp_turn_detector.py."
+            "FT-N-02 full replay requires `E2E_SITL_REPLAY_DIR` to point at a "
+            "prepared SITL replay fixture (AZ-595). AC-2/AC-3 helper logic "
+            "covered by e2e/_unit_tests/helpers/test_sharp_turn_detector.py."
         )
 
     from runner.helpers import fdr_reader

e2e/tests/negative/test_ft_n_03_outage_reloc.py

@@ -31,39 +31,6 @@ DERKACHI_DIR = (
 DERKACHI_MP4 = DERKACHI_DIR / "flight_derkachi.mp4"
 
 
-@pytest.fixture(scope="module")
-def _harness_helpers_implemented() -> bool:
-    from runner.helpers import fdr_reader, mavproxy_tlog_reader, sitl_observer
-    from runner.helpers.frame_source_replay import FrameSourceReplayer
-
-    try:
-        replayer = FrameSourceReplayer(sink=_NullSink())  # type: ignore[arg-type]
-        try:
-            replayer.replay_video(Path("/tmp/non-existent.mp4"))
-        except NotImplementedError:
-            return False
-        try:
-            list(fdr_reader.iter_records(Path("/tmp/non-existent")))
-        except NotImplementedError:
-            return False
-        try:
-            list(mavproxy_tlog_reader.iter_messages(Path("/tmp/non-existent.tlog")))
-        except NotImplementedError:
-            return False
-        try:
-            sitl_observer.read_ekf_divergence_events()  # type: ignore[attr-defined]
-        except (AttributeError, NotImplementedError):
-            return False
-        return True
-    except Exception:
-        return False
-
-
-class _NullSink:
-    def write_frame(self, jpeg_bytes: bytes, timestamp_ms: int) -> None:
-        return None
-
-
 @pytest.mark.traces_to("AC-3.4,AC-1,AC-2,AC-3,AC-4,AC-5")
 def test_ft_n_03_outage_reloc(
     fc_adapter: str,
@@ -71,13 +38,12 @@ def test_ft_n_03_outage_reloc(
     evidence_dir,  # type: ignore[no-untyped-def]
     run_id: str,
     nfr_recorder,  # type: ignore[no-untyped-def]
-    _harness_helpers_implemented: bool,
+    sitl_replay_ready: bool,
 ) -> None:
-    if not _harness_helpers_implemented:
+    if not sitl_replay_ready:
         pytest.skip(
-            "FT-N-03 full replay requires runner.helpers.{frame_source_replay,"
-            "fdr_reader,mavproxy_tlog_reader,sitl_observer} — currently "
-            "AZ-441 / AZ-407 / AZ-416 leftovers. AC-1..AC-4 evaluator logic "
+            "FT-N-03 full replay requires `E2E_SITL_REPLAY_DIR` to point at a "
+            "prepared SITL replay fixture (AZ-595). AC-1..AC-4 evaluator logic "
             "covered by e2e/_unit_tests/helpers/test_outage_request_evaluator.py."
         )
 

e2e/tests/negative/test_ft_n_04_blackout_spoof.py

@@ -26,40 +26,6 @@ from runner.helpers import blackout_spoof_evaluator as bse
 _WINDOW_LADDER_S = (5.0, 15.0, 35.0)
 
 
-@pytest.fixture(scope="module")
-def _harness_helpers_implemented() -> bool:
-    from runner.helpers import fdr_reader, mavproxy_tlog_reader, sitl_observer
-    from runner.helpers.frame_source_replay import FrameSourceReplayer
-
-    try:
-        replayer = FrameSourceReplayer(sink=_NullSink())  # type: ignore[arg-type]
-        try:
-            replayer.replay_video(Path("/tmp/non-existent.mp4"))
-        except NotImplementedError:
-            return False
-        try:
-            list(fdr_reader.iter_records(Path("/tmp/non-existent")))
-        except NotImplementedError:
-            return False
-        try:
-            list(mavproxy_tlog_reader.iter_messages(Path("/tmp/non-existent.tlog")))
-        except NotImplementedError:
-            return False
-        try:
-            sitl_observer.read_gps_health_samples()  # type: ignore[attr-defined]
-            sitl_observer.read_consistency_check_events()  # type: ignore[attr-defined]
-        except (AttributeError, NotImplementedError):
-            return False
-        return True
-    except Exception:
-        return False
-
-
-class _NullSink:
-    def write_frame(self, jpeg_bytes: bytes, timestamp_ms: int) -> None:
-        return None
-
-
 @pytest.mark.parametrize(
     "blackout_spoof_derkachi",
     [{"window_seconds": s, "seed": 0} for s in _WINDOW_LADDER_S],
@@ -76,14 +42,14 @@ def test_ft_n_04_blackout_spoof(
     evidence_dir,  # type: ignore[no-untyped-def]
     run_id: str,
     nfr_recorder,  # type: ignore[no-untyped-def]
-    _harness_helpers_implemented: bool,
+    sitl_replay_ready: bool,
 ) -> None:
-    if not _harness_helpers_implemented:
+    if not sitl_replay_ready:
         pytest.skip(
-            "FT-N-04 full replay requires runner.helpers.{frame_source_replay,"
-            "fdr_reader,mavproxy_tlog_reader,sitl_observer,fc_proxy} — currently "
-            "AZ-441 / AZ-407 / AZ-416 leftovers. AC-1..AC-8 evaluator logic "
-            "covered by e2e/_unit_tests/helpers/test_blackout_spoof_evaluator.py."
+            "FT-N-04 full replay requires `E2E_SITL_REPLAY_DIR` to point at a "
+            "prepared SITL replay fixture (AZ-595) AND a runtime fc_proxy "
+            "driver. AC-1..AC-8 evaluator logic covered by "
+            "e2e/_unit_tests/helpers/test_blackout_spoof_evaluator.py."
         )
 
     from runner.helpers import fdr_reader, mavproxy_tlog_reader, sitl_observer