SerialHandler: Raise exceptions on unrecoverable errors

Author: bessman

pslab/serial_handler.py

@@ -83,7 +83,7 @@ def _check_udev():
                 raise OSError(e)
 
     @staticmethod
-    def _list_ports() -> List[str]:  # Promote to public?
+    def _list_ports() -> List[str]:
         """Return a list of serial port names."""
         return [p.device for p in list_ports.comports()]
 
@@ -196,26 +196,31 @@ def get_version(self) -> str:
         self._write_log(version, "RX")
         return version.decode("utf-8")
 
-    def get_ack(self) -> int:  # Make _internal?
+    def get_ack(self) -> int:
         """Get response code from PSLab.
 
-        Also functions as handshake.
-
         Returns
         -------
         int
             Response code. Meanings:
-                1 SUCCESS
-                2 ARGUMENT_ERROR
-                3 FAILED
+                0x01 ACK
+                0x10 I2C ACK
+                0x20 I2C bus collision
+                0x10 Radio max retransmits
+                0x20 Radio not present
+                0x40 Radio reply timout
         """
         response = self.read(1)
 
-        try:
-            return CP.Byte.unpack(response)[0]
-        except Exception as e:
-            logger.error(e)
-            return 3  # raise exception instead?
+        if not response:
+            raise serial.SerialException("Timeout while waiting for ACK.")
+
+        ack = CP.Byte.unpack(response)[0]
+
+        if not (ack & 0x01):
+            raise serial.SerialException("Received non ACK byte while waiting for ACK.")
+
+        return ack
 
     @staticmethod
     def _get_integer_type(size: int) -> struct.Struct:
@@ -250,16 +255,21 @@ def _receive(self, size: int) -> int:
         Returns
         -------
         int
-            Unpacked data, or -1 if too few bytes were read.
+            Unpacked data.
+
+        Raises
+        ------
+        SerialException if too few bytes received.
         """
         received = self.read(size)
 
         if len(received) == size:
             unpacker = self._get_integer_type(size)
             retval = unpacker.unpack(received)[0]
         else:
-            logger.error(f"Requested {size} bytes, got {len(received)}.")
-            retval = -1  # raise an exception instead?
+            raise serial.SerialException(
+                f"Requested {size} bytes, got {len(received)}."
+            )
 
         return retval
 

tests/recordings/i2c/test_scan.json

@@ -1 +1 @@
-[[[4], [14], [4], [9], [148, 0], [4], [16], [4], [1], [3], [4], [3], [4], [1], [5], [4], [3], [4], [1], [7], [4], [3], [4], [1], [9], [4], [3], [4], [1], [11], [4], [3], [4], [1], [13], [4], [3], [4], [1], [15], [4], [3], [4], [1], [17], [4], [3], [4], [1], [19], [4], [3], [4], [1], [21], [4], [3], [4], [1], [23], [4], [3], [4], [1], [25], [4], [3], [4], [1], [27], [4], [3], [4], [1], [29], [4], [3], [4], [1], [31], [4], [3], [4], [1], [33], [4], [3], [4], [1], [35], [4], [3], [4], [1], [37], [4], [3], [4], [1], [39], [4], [3], [4], [1], [41], [4], [3], [4], [1], [43], [4], [3], [4], [1], [45], [4], [3], [4], [1], [47], [4], [3], [4], [1], [49], [4], [3], [4], [1], [51], [4], [3], [4], [1], [53], [4], [3], [4], [1], [55], [4], [3], [4], [1], [57], [4], [3], [4], [1], [59], [4], [3], [4], [1], [61], [4], [3], [4], [1], [63], [4], [3], [4], [1], [65], [4], [3], [4], [1], [67], [4], [3], [4], [1], [69], [4], [3], [4], [1], [71], [4], [3], [4], [1], [73], [4], [3], [4], [1], [75], [4], [3], [4], [1], [77], [4], [3], [4], [1], [79], [4], [3], [4], [1], [81], [4], [3], [4], [1], [83], [4], [3], [4], [1], [85], [4], [3], [4], [1], [87], [4], [3], [4], [1], [89], [4], [3], [4], [1], [91], [4], [3], [4], [1], [93], [4], [3], [4], [1], [95], [4], [3], [4], [1], [97], [4], [3], [4], [1], [99], [4], [3], [4], [1], [101], [4], [3], [4], [1], [103], [4], [3], [4], [1], [105], [4], [3], [4], [1], [107], [4], [3], [4], [1], [109], [4], [3], [4], [1], [111], [4], [3], [4], [1], [113], [4], [3], [4], [1], [115], [4], [3], [4], [1], [117], [4], [3], [4], [1], [119], [4], [3], [4], [1], [121], [4], [3], [4], [1], [123], [4], [3], [4], [1], [125], [4], [3], [4], [1], [127], [4], [3], [4], [1], [129], [4], [3], [4], [1], [131], [4], [3], [4], [1], [133], [4], [3], [4], [1], [135], [4], [3], [4], [1], [137], [4], [3], [4], [1], [139], [4], [3], [4], [1], [141], [4], [3], [4], [1], [143], [4], [3], [4], [1], [145], [4], [3], [4], [1], [147], [4], [3], [4], [1], [149], [4], [3], [4], [1], [151], [4], [3], [4], [1], [153], [4], [3], [4], [1], [155], [4], [3], [4], [1], [157], [4], [3], [4], [1], [159], [4], [3], [4], [1], [161], [4], [3], [4], [1], [163], [4], [3], [4], [1], [165], [4], [3], [4], [1], [167], [4], [3], [4], [1], [169], [4], [3], [4], [1], [171], [4], [3], [4], [1], [173], [4], [3], [4], [1], [175], [4], [3], [4], [1], [177], [4], [3], [4], [1], [179], [4], [3], [4], [1], [181], [4], [3], [4], [1], [183], [4], [3], [4], [1], [185], [4], [3], [4], [1], [187], [4], [3], [4], [1], [189], [4], [3], [4], [1], [191], [4], [3], [4], [1], [193], [4], [3], [4], [1], [195], [4], [3], [4], [1], [197], [4], [3], [4], [1], [199], [4], [3], [4], [1], [201], [4], [3], [4], [1], [203], [4], [3], [4], [1], [205], [4], [3], [4], [1], [207], [4], [3], [4], [1], [209], [4], [3], [4], [1], [211], [4], [3], [4], [1], [213], [4], [3], [4], [1], [215], [4], [3], [4], [1], [217], [4], [3], [4], [1], [219], [4], [3], [4], [1], [221], [4], [3], [4], [1], [223], [4], [3], [4], [1], [225], [4], [3], [4], [1], [227], [4], [3], [4], [1], [229], [4], [3], [4], [1], [231], [4], [3], [4], [1], [233], [4], [3], [4], [1], [235], [4], [3], [4], [1], [237], [4], [3], [4], [1], [239], [4], [3], [4], [1], [241], [4], [3], [4], [1], [243], [4], [3], [4], [1], [245], [4], [3], [4], [1], [247], [4], [3], [4], [1], [249], [4], [3], [4], [1], [251], [4], [3], [4], [1], [253], [4], [3], [4], [1], [255], [4], [3]], [[], [1], [], [], [1], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [1], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1]]]
+[[[4], [14], [4], [9], [244, 1], [4], [1], [3], [4], [3], [4], [1], [5], [4], [3], [4], [1], [7], [4], [3], [4], [1], [9], [4], [3], [4], [1], [11], [4], [3], [4], [1], [13], [4], [3], [4], [1], [15], [4], [3], [4], [1], [17], [4], [3], [4], [1], [19], [4], [3], [4], [1], [21], [4], [3], [4], [1], [23], [4], [3], [4], [1], [25], [4], [3], [4], [1], [27], [4], [3], [4], [1], [29], [4], [3], [4], [1], [31], [4], [3], [4], [1], [33], [4], [3], [4], [1], [35], [4], [3], [4], [1], [37], [4], [3], [4], [1], [39], [4], [3], [4], [1], [41], [4], [3], [4], [1], [43], [4], [3], [4], [1], [45], [4], [3], [4], [1], [47], [4], [3], [4], [1], [49], [4], [3], [4], [1], [51], [4], [3], [4], [1], [53], [4], [3], [4], [1], [55], [4], [3], [4], [1], [57], [4], [3], [4], [1], [59], [4], [3], [4], [1], [61], [4], [3], [4], [1], [63], [4], [3], [4], [1], [65], [4], [3], [4], [1], [67], [4], [3], [4], [1], [69], [4], [3], [4], [1], [71], [4], [3], [4], [1], [73], [4], [3], [4], [1], [75], [4], [3], [4], [1], [77], [4], [3], [4], [1], [79], [4], [3], [4], [1], [81], [4], [3], [4], [1], [83], [4], [3], [4], [1], [85], [4], [3], [4], [1], [87], [4], [3], [4], [1], [89], [4], [3], [4], [1], [91], [4], [3], [4], [1], [93], [4], [3], [4], [1], [95], [4], [3], [4], [1], [97], [4], [3], [4], [1], [99], [4], [3], [4], [1], [101], [4], [3], [4], [1], [103], [4], [3], [4], [1], [105], [4], [3], [4], [1], [107], [4], [3], [4], [1], [109], [4], [3], [4], [1], [111], [4], [3], [4], [1], [113], [4], [3], [4], [1], [115], [4], [3], [4], [1], [117], [4], [3], [4], [1], [119], [4], [3], [4], [1], [121], [4], [3], [4], [1], [123], [4], [3], [4], [1], [125], [4], [3], [4], [1], [127], [4], [3], [4], [1], [129], [4], [3], [4], [1], [131], [4], [3], [4], [1], [133], [4], [3], [4], [1], [135], [4], [3], [4], [1], [137], [4], [3], [4], [1], [139], [4], [3], [4], [1], [141], [4], [3], [4], [1], [143], [4], [3], [4], [1], [145], [4], [3], [4], [1], [147], [4], [3], [4], [1], [149], [4], [3], [4], [1], [151], [4], [3], [4], [1], [153], [4], [3], [4], [1], [155], [4], [3], [4], [1], [157], [4], [3], [4], [1], [159], [4], [3], [4], [1], [161], [4], [3], [4], [1], [163], [4], [3], [4], [1], [165], [4], [3], [4], [1], [167], [4], [3], [4], [1], [169], [4], [3], [4], [1], [171], [4], [3], [4], [1], [173], [4], [3], [4], [1], [175], [4], [3], [4], [1], [177], [4], [3], [4], [1], [179], [4], [3], [4], [1], [181], [4], [3], [4], [1], [183], [4], [3], [4], [1], [185], [4], [3], [4], [1], [187], [4], [3], [4], [1], [189], [4], [3], [4], [1], [191], [4], [3], [4], [1], [193], [4], [3], [4], [1], [195], [4], [3], [4], [1], [197], [4], [3], [4], [1], [199], [4], [3], [4], [1], [201], [4], [3], [4], [1], [203], [4], [3], [4], [1], [205], [4], [3], [4], [1], [207], [4], [3], [4], [1], [209], [4], [3], [4], [1], [211], [4], [3], [4], [1], [213], [4], [3], [4], [1], [215], [4], [3], [4], [1], [217], [4], [3], [4], [1], [219], [4], [3], [4], [1], [221], [4], [3], [4], [1], [223], [4], [3], [4], [1], [225], [4], [3], [4], [1], [227], [4], [3], [4], [1], [229], [4], [3], [4], [1], [231], [4], [3], [4], [1], [233], [4], [3], [4], [1], [235], [4], [3], [4], [1], [237], [4], [3], [4], [1], [239], [4], [3], [4], [1], [241], [4], [3], [4], [1], [243], [4], [3], [4], [1], [245], [4], [3], [4], [1], [247], [4], [3], [4], [1], [249], [4], [3], [4], [1], [251], [4], [3], [4], [1], [253], [4], [3], [4], [1], [255], [4], [3]], [[], [1], [], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [1], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1], [], [], [17], [], [1]]]

tests/test_serial_handler.py

@@ -74,9 +74,9 @@ def test_get_ack_success(mock_serial, mock_handler):
 
 
 def test_get_ack_failure(mock_serial, mock_handler):
-    error = 3
     mock_serial().read.return_value = b""
-    assert mock_handler.get_ack() == error
+    with pytest.raises(SerialException):
+        mock_handler.get_ack()
 
 
 def test_send_bytes(mock_serial, mock_handler):
@@ -98,9 +98,8 @@ def test_receive(mock_serial, mock_handler):
 
 def test_receive_failure(mock_serial, mock_handler):
     mock_serial().read.return_value = b""
-    r = mock_handler.get_byte()
-    mock_serial().read.assert_called_with(1)
-    assert r == -1
+    with pytest.raises(SerialException):
+        mock_handler.get_byte()
 
 
 def test_wait_for_data(mock_serial, mock_handler):