cpython/Lib/test/test_exception_hierarchy.py

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import builtins
import os
import select
import socket
import unittest
import errno
from errno import EEXIST
class SubOSError(OSError):
pass
class SubOSErrorWithInit(OSError):
def __init__(self, message, bar):
self.bar = bar
super().__init__(message)
class SubOSErrorWithNew(OSError):
def __new__(cls, message, baz):
self = super().__new__(cls, message)
self.baz = baz
return self
class SubOSErrorCombinedInitFirst(SubOSErrorWithInit, SubOSErrorWithNew):
pass
class SubOSErrorCombinedNewFirst(SubOSErrorWithNew, SubOSErrorWithInit):
pass
class SubOSErrorWithStandaloneInit(OSError):
def __init__(self):
pass
class HierarchyTest(unittest.TestCase):
def test_builtin_errors(self):
self.assertEqual(OSError.__name__, 'OSError')
self.assertIs(IOError, OSError)
self.assertIs(EnvironmentError, OSError)
def test_socket_errors(self):
self.assertIs(socket.error, IOError)
self.assertIs(socket.gaierror.__base__, OSError)
self.assertIs(socket.herror.__base__, OSError)
self.assertIs(socket.timeout.__base__, OSError)
def test_select_error(self):
self.assertIs(select.error, OSError)
# mmap.error is tested in test_mmap
_pep_map = """
+-- BlockingIOError EAGAIN, EALREADY, EWOULDBLOCK, EINPROGRESS
+-- ChildProcessError ECHILD
+-- ConnectionError
+-- BrokenPipeError EPIPE, ESHUTDOWN
+-- ConnectionAbortedError ECONNABORTED
+-- ConnectionRefusedError ECONNREFUSED
+-- ConnectionResetError ECONNRESET
+-- FileExistsError EEXIST
+-- FileNotFoundError ENOENT
+-- InterruptedError EINTR
+-- IsADirectoryError EISDIR
+-- NotADirectoryError ENOTDIR
+-- PermissionError EACCES, EPERM
+-- ProcessLookupError ESRCH
+-- TimeoutError ETIMEDOUT
"""
def _make_map(s):
_map = {}
for line in s.splitlines():
line = line.strip('+- ')
if not line:
continue
excname, _, errnames = line.partition(' ')
for errname in filter(None, errnames.strip().split(', ')):
_map[getattr(errno, errname)] = getattr(builtins, excname)
return _map
_map = _make_map(_pep_map)
def test_errno_mapping(self):
# The OSError constructor maps errnos to subclasses
# A sample test for the basic functionality
e = OSError(EEXIST, "Bad file descriptor")
self.assertIs(type(e), FileExistsError)
# Exhaustive testing
for errcode, exc in self._map.items():
e = OSError(errcode, "Some message")
self.assertIs(type(e), exc)
othercodes = set(errno.errorcode) - set(self._map)
for errcode in othercodes:
e = OSError(errcode, "Some message")
self.assertIs(type(e), OSError)
def test_try_except(self):
filename = "some_hopefully_non_existing_file"
# This checks that try .. except checks the concrete exception
# (FileNotFoundError) and not the base type specified when
# PyErr_SetFromErrnoWithFilenameObject was called.
# (it is therefore deliberate that it doesn't use assertRaises)
try:
open(filename)
except FileNotFoundError:
pass
else:
self.fail("should have raised a FileNotFoundError")
# Another test for PyErr_SetExcFromWindowsErrWithFilenameObject()
self.assertFalse(os.path.exists(filename))
try:
os.unlink(filename)
except FileNotFoundError:
pass
else:
self.fail("should have raised a FileNotFoundError")
class AttributesTest(unittest.TestCase):
def test_windows_error(self):
if os.name == "nt":
self.assertIn('winerror', dir(OSError))
else:
self.assertNotIn('winerror', dir(OSError))
def test_posix_error(self):
e = OSError(EEXIST, "File already exists", "foo.txt")
self.assertEqual(e.errno, EEXIST)
self.assertEqual(e.args[0], EEXIST)
self.assertEqual(e.strerror, "File already exists")
self.assertEqual(e.filename, "foo.txt")
if os.name == "nt":
self.assertEqual(e.winerror, None)
@unittest.skipUnless(os.name == "nt", "Windows-specific test")
def test_errno_translation(self):
# ERROR_ALREADY_EXISTS (183) -> EEXIST
e = OSError(0, "File already exists", "foo.txt", 183)
self.assertEqual(e.winerror, 183)
self.assertEqual(e.errno, EEXIST)
self.assertEqual(e.args[0], EEXIST)
self.assertEqual(e.strerror, "File already exists")
self.assertEqual(e.filename, "foo.txt")
def test_blockingioerror(self):
args = ("a", "b", "c", "d", "e")
for n in range(6):
e = BlockingIOError(*args[:n])
with self.assertRaises(AttributeError):
e.characters_written
with self.assertRaises(AttributeError):
del e.characters_written
e = BlockingIOError("a", "b", 3)
self.assertEqual(e.characters_written, 3)
e.characters_written = 5
self.assertEqual(e.characters_written, 5)
del e.characters_written
with self.assertRaises(AttributeError):
e.characters_written
class ExplicitSubclassingTest(unittest.TestCase):
def test_errno_mapping(self):
# When constructing an OSError subclass, errno mapping isn't done
e = SubOSError(EEXIST, "Bad file descriptor")
self.assertIs(type(e), SubOSError)
def test_init_overridden(self):
e = SubOSErrorWithInit("some message", "baz")
self.assertEqual(e.bar, "baz")
self.assertEqual(e.args, ("some message",))
def test_init_kwdargs(self):
e = SubOSErrorWithInit("some message", bar="baz")
self.assertEqual(e.bar, "baz")
self.assertEqual(e.args, ("some message",))
def test_new_overridden(self):
e = SubOSErrorWithNew("some message", "baz")
self.assertEqual(e.baz, "baz")
self.assertEqual(e.args, ("some message",))
def test_new_kwdargs(self):
e = SubOSErrorWithNew("some message", baz="baz")
self.assertEqual(e.baz, "baz")
self.assertEqual(e.args, ("some message",))
def test_init_new_overridden(self):
e = SubOSErrorCombinedInitFirst("some message", "baz")
self.assertEqual(e.bar, "baz")
self.assertEqual(e.baz, "baz")
self.assertEqual(e.args, ("some message",))
e = SubOSErrorCombinedNewFirst("some message", "baz")
self.assertEqual(e.bar, "baz")
self.assertEqual(e.baz, "baz")
self.assertEqual(e.args, ("some message",))
def test_init_standalone(self):
# __init__ doesn't propagate to OSError.__init__ (see issue #15229)
e = SubOSErrorWithStandaloneInit()
self.assertEqual(e.args, ())
self.assertEqual(str(e), '')
if __name__ == "__main__":
unittest.main()