raise error when an error frame is detected.

hardware/opentrons_hardware/drivers/can_bus/driver.py

@@ -9,6 +9,8 @@
 
 from .arbitration_id import ArbitrationId
 from .message import CanMessage
+from .errors import ErrorFrameCanError
+
 
 if platform.system() == "Darwin":
     # TODO (amit, 2021-09-29): remove hacks to support `pcan` when we don't
@@ -112,9 +114,15 @@ async def read(self) -> CanMessage:
 
         Returns:
             A can message
+
+        Raises:
+            ErrorFrameCanError
         """
         ...
         m: Message = await self._reader.get_message()
+        if m.is_error_frame:
+            raise ErrorFrameCanError(message=repr(m))
+
         return CanMessage(
             arbitration_id=ArbitrationId(id=m.arbitration_id), data=m.data
         )

hardware/opentrons_hardware/drivers/can_bus/errors.py

@@ -0,0 +1,15 @@
+"""Can bus errors."""
+
+
+class CanError(Exception):
+    """Can bus error."""
+
+    def __init__(self, message: str) -> None:
+        """Constructor."""
+        super().__init__(message)
+
+
+class ErrorFrameCanError(CanError):
+    """An error frame was received on the can bus."""
+
+    pass

hardware/tests/opentrons_hardware/drivers/can_bus/test_driver.py

@@ -6,6 +6,7 @@
 from can import Bus, Message
 
 from opentrons_hardware.drivers.can_bus import CanDriver, ArbitrationId, CanMessage
+from opentrons_hardware.drivers.can_bus.errors import ErrorFrameCanError
 
 
 @pytest.fixture
@@ -89,3 +90,17 @@ async def test_receive_iter(subject: CanDriver, can_bus: Bus) -> None:
     assert received[0].arbitration_id.id == 0x1FFFFFFF
     assert received[1].data == bytearray([4, 3, 2, 1])
     assert received[1].arbitration_id.id == 0
+
+
+async def test_raise_error_frame_error(subject: CanDriver, can_bus: Bus) -> None:
+    """It should raise an error when an error frame is received."""
+    m = Message(
+        arbitration_id=0x1FFFFFFF,
+        is_extended_id=True,
+        is_error_frame=True,
+        is_fd=True,
+        data=bytearray([1, 2, 3, 4]),
+    )
+    can_bus.send(m)
+    with pytest.raises(ErrorFrameCanError):
+        await subject.read()