cleanups in socketcan helpers

felixdivo · felixdivo · commit 8fc1b62b74cc · 2020-02-11T15:53:15.000+01:00
diff --git a/can/interfaces/socketcan/utils.py b/can/interfaces/socketcan/utils.py
@@ -2,17 +2,16 @@
 Defines common socketcan functions.
 """
 
-from typing import cast, Iterable, Optional
-import can.typechecking as typechecking
-
 import logging
 import os
 import errno
 import struct
 import subprocess
 import re
+from typing import cast, Iterable, Optional
 
 from can.interfaces.socketcan.constants import CAN_EFF_FLAG
+import can.typechecking as typechecking
 
 log = logging.getLogger(__name__)
 
@@ -49,11 +48,11 @@ def find_available_interfaces() -> Iterable[str]:
     """
 
     try:
-        # it might be good to add "type vcan", but that might (?) exclude physical can devices
+        # adding "type vcan" would exclude physical can devices
         command = ["ip", "-o", "link", "list", "up"]
         output = subprocess.check_output(command, universal_newlines=True)
 
-    except Exception as e:  # subprocess.CalledProcessError was too specific
+    except Exception as e:  # subprocess.CalledProcessError is too specific
         log.error("failed to fetch opened can devices: %s", e)
         return []
 
@@ -66,23 +65,15 @@ def find_available_interfaces() -> Iterable[str]:
         return filter(_PATTERN_CAN_INTERFACE.match, interface_names)
 
 
-def error_code_to_str(code: int) -> str:
+def error_code_to_str(code: Optional[int]) -> str:
     """
     Converts a given error code (errno) to a useful and human readable string.
 
     :param code: a possibly invalid/unknown error code
     :returns: a string explaining and containing the given error code, or a string
               explaining that the errorcode is unknown if that is the case
     """
+    name = errno.errorcode.get(code, "UNKNOWN")
+    description = os.strerror(code)
 
-    try:
-        name = errno.errorcode[code]
-    except KeyError:
-        name = "UNKNOWN"
-
-    try:
-        description = os.strerror(code)
-    except ValueError:
-        description = "no description available"
-
-    return "{} (errno {}): {}".format(name, code, description)
+    return f"{name} (errno {code}): {description}"
diff --git a/test/test_socketcan_helpers.py b/test/test_socketcan_helpers.py
@@ -9,10 +9,11 @@
 
 from can.interfaces.socketcan.utils import find_available_interfaces, error_code_to_str
 
-from .config import *
+from .config import IS_LINUX, TEST_INTERFACE_SOCKETCAN
 
 
 class TestSocketCanHelpers(unittest.TestCase):
+
     @unittest.skipUnless(IS_LINUX, "socketcan is only available on Linux")
     def test_error_code_to_str(self):
         """
