[AZ-558] Route C8 outbound encoder bytes through MavlinkTransport seam

All FC adapter outbound MAVLink bytes now go through the AZ-401 MavlinkTransport seam (NoopMavlinkTransport in replay, SerialMavlinkTransport in live). New helpers in _outbound_mavlink_payloads.py extract encode/pack/seq-bump so the four AP _send sites and the iNav statustext _send site become encode -> pack -> transport.write. TlogReplayFcAdapter emits real AP-shape MAVLink bytes through the injected NoopMavlinkTransport, satisfying replay protocol Invariant 5 and unblocking AZ-401 AC-9. Closes AZ-558. Also unskips AZ-401 AC-9 and AZ-404 AC-4b. Live wire output remains byte-identical (proven via two-instance MAVLink byte-equivalence tests). AST scan asserts no .mav.<name>_send( calls remain in the retrofit set (AP / iNav / tlog adapters). Out of scope (logged in review): GCS adapter retrofit; airborne live strategy registration that would activate the SerialMavlinkTransport factory injection path. Tests: 2110 passed, 92 environmental skips, 1 unrelated pre-existing macOS cold-start flake deselected. Co-authored-by: Cursor <cursoragent@cursor.com>
2026-06-22 21:41:13 +00:00 · 2026-05-16 05:33:45 +03:00
parent d7e6b0959e
commit 2b19b8b90b
18 changed files with 1106 additions and 90 deletions
@@ -266,19 +266,84 @@ class _ModeBranchScanner(ast.NodeVisitor):


 # ----------------------------------------------------------------------
-# AC-4b: Encoder byte-equality (BLOCKED on AZ-558)
+# AC-4b: Encoder byte-equality (closed by AZ-558)


-@pytest.mark.skip(
-    reason=(
-        "AC-4b blocked on AZ-558: C8 encoders still bypass the "
-        "MavlinkTransport seam by calling mav.*_send directly. The "
-        "CapturingMavlinkTransport fixture in _helpers.py is ready; "
-        "this test unskips when AZ-558 lands."
+def test_ac4_encoder_byte_equality_via_transport_seam() -> None:
+    """AZ-404 AC-4b / AZ-558 AC-2: encoders write the same bytes through
+    the :class:`MavlinkTransport` seam regardless of mode.
+
+    Constructive equivalence: pymavlink's ``MAVLink.send`` and our
+    retrofit (``mav.X_encode → msg.pack(mav) → transport.write``)
+    both invoke ``pack`` on the same MAVLink instance with the same
+    pre-bump ``mav.seq``. Run both paths with two MAVLink instances
+    initialised identically; the resulting bytes are equal by
+    construction.
+
+    AZ-558's unit suite (``test_az558_outbound_transport_seam.py``)
+    covers this for every retrofitted message kind (GPS_INPUT,
+    NAMED_VALUE_FLOAT, STATUSTEXT, multi-message seq alignment); this
+    e2e variant double-checks the contract holds against the live
+    pymavlink ``MAVLink.send`` integration so a future pymavlink
+    upgrade that changes the framing surface fails this test loudly.
+    """
+    # Arrange
+    import io
+
+    from pymavlink.dialects.v20 import ardupilotmega as _mavlink
+
+    from gps_denied_onboard.components.c8_fc_adapter._outbound_mavlink_payloads import (
+        encode_gps_input,
+        send_via_transport,
    )
-)
-def test_ac4_encoder_byte_equality() -> None:
-    raise NotImplementedError("blocked on AZ-558 — see skip reason")
+
+    from tests.e2e.replay._helpers import CapturingMavlinkTransport
+
+    legacy_buf = io.BytesIO()
+    legacy = _mavlink.MAVLink(file=legacy_buf, srcSystem=1, srcComponent=1)
+    new = _mavlink.MAVLink(file=None, srcSystem=1, srcComponent=1)
+    capture = CapturingMavlinkTransport()
+
+    # Three deterministic GPS_INPUT messages of varying intensity to
+    # cover the encoded-payload range.
+    samples = [
+        dict(
+            time_usec=t * 100_000,
+            gps_id=0,
+            ignore_flags=0,
+            time_week_ms=0,
+            time_week=0,
+            fix_type=3,
+            lat=int((50.0 + t * 0.0001) * 1e7),
+            lon=int((30.0 + t * 0.0001) * 1e7),
+            alt=100.0 + t * 0.5,
+            hdop=0.0,
+            vdop=0.0,
+            vn=0.0,
+            ve=0.0,
+            vd=0.0,
+            speed_accuracy=0.0,
+            horiz_accuracy=2.0 + t * 0.1,
+            vert_accuracy=0.0,
+            satellites_visible=10,
+            yaw=0,
+        )
+        for t in range(3)
+    ]
+
+    # Act
+    for s in samples:
+        legacy.gps_input_send(*s.values())
+        msg = encode_gps_input(new, **s)
+        send_via_transport(new, msg, capture)
+
+    # Assert
+    assert legacy_buf.getvalue() == capture.captured_concat, (
+        "AZ-404 AC-4b violated: encoder byte stream differs between "
+        "MAVLink.send and encode→pack→transport.write paths"
+    )
+    assert capture.bytes_written() > 0
+    assert legacy.seq == new.seq


 # ----------------------------------------------------------------------