Fixed #30137 -- Replaced OSError aliases with the canonical OSError.

Used more specific errors (e.g. FileExistsError) as appropriate.

14 files changed, 30 insertions, 36 deletions

diff --git a/tests/admin_widgets/tests.py b/tests/admin_widgets/tests.py
index 623fa39bc1..a7335f8f69 100644
--- a/tests/admin_widgets/tests.py
+++ b/tests/admin_widgets/tests.py
@@ -867,7 +867,7 @@ class DateTimePickerSeleniumTests(AdminWidgetSeleniumTestCase):
         for language_code, language_name in settings.LANGUAGES:
             try:
                 catalog = gettext.translation('djangojs', path, [language_code])
-            except IOError:
+            except OSError:
                 continue
             if month_string in catalog._catalog:
                 month_name = catalog._catalog[month_string]
diff --git a/tests/cache/tests.py b/tests/cache/tests.py
index 0dd9208710..9f717cfa23 100644
--- a/tests/cache/tests.py
+++ b/tests/cache/tests.py
@@ -1448,8 +1448,8 @@ class FileBasedCacheTests(BaseCacheTests, TestCase):
         self.assertEqual(cache.get('foo', 'baz'), 'baz')
 
     def test_get_does_not_ignore_non_filenotfound_exceptions(self):
-        with mock.patch('builtins.open', side_effect=IOError):
-            with self.assertRaises(IOError):
+        with mock.patch('builtins.open', side_effect=OSError):
+            with self.assertRaises(OSError):
                 cache.get('foo')
 
     def test_empty_cache_file_considered_expired(self):
diff --git a/tests/csrf_tests/tests.py b/tests/csrf_tests/tests.py
index 2c40e44ae1..59abc6da32 100644
--- a/tests/csrf_tests/tests.py
+++ b/tests/csrf_tests/tests.py
@@ -441,12 +441,12 @@ class CsrfViewMiddlewareTestMixin:
 
     def test_post_data_read_failure(self):
         """
-        #20128 -- IOErrors during POST data reading should be caught and
-        treated as if the POST data wasn't there.
+        OSErrors during POST data reading are caught and treated as if the
+        POST data wasn't there (#20128).
         """
         class CsrfPostRequest(HttpRequest):
             """
-            HttpRequest that can raise an IOError when accessing POST data
+            HttpRequest that can raise an OSError when accessing POST data
             """
             def __init__(self, token, raise_error):
                 super().__init__()
@@ -464,7 +464,7 @@ class CsrfViewMiddlewareTestMixin:
                 self.raise_error = raise_error
 
             def _load_post_and_files(self):
-                raise IOError('error reading input data')
+                raise OSError('error reading input data')
 
             def _get_post(self):
                 if self.raise_error:
diff --git a/tests/file_storage/tests.py b/tests/file_storage/tests.py
index 8c50abc9b0..991f1ff8cd 100644
--- a/tests/file_storage/tests.py
+++ b/tests/file_storage/tests.py
@@ -482,9 +482,9 @@ class FileStorageTests(SimpleTestCase):
         f1 = ContentFile('chunks fails')
 
         def failing_chunks():
-            raise IOError
+            raise OSError
         f1.chunks = failing_chunks
-        with self.assertRaises(IOError):
+        with self.assertRaises(OSError):
             self.storage.save('error.file', f1)
 
     def test_delete_no_name(self):
diff --git a/tests/file_uploads/tests.py b/tests/file_uploads/tests.py
index fb333dcf13..07a9d9b647 100644
--- a/tests/file_uploads/tests.py
+++ b/tests/file_uploads/tests.py
@@ -548,16 +548,13 @@ class DirectoryCreationTests(SimpleTestCase):
             self.obj.testfile.save('foo.txt', SimpleUploadedFile('foo.txt', b'x'), save=False)
 
     def test_not_a_directory(self):
-        """The correct IOError is raised when the upload directory name exists but isn't a directory"""
         # Create a file with the upload directory name
         open(UPLOAD_TO, 'wb').close()
         self.addCleanup(os.remove, UPLOAD_TO)
-        with self.assertRaises(IOError) as exc_info:
+        msg = '%s exists and is not a directory.' % UPLOAD_TO
+        with self.assertRaisesMessage(FileExistsError, msg):
             with SimpleUploadedFile('foo.txt', b'x') as file:
                 self.obj.testfile.save('foo.txt', file, save=False)
-        # The test needs to be done on a specific string as IOError
-        # is raised even without the patch (just not early enough)
-        self.assertEqual(exc_info.exception.args[0], "%s exists and is not a directory." % UPLOAD_TO)
 
 
 class MultiParserTests(SimpleTestCase):
diff --git a/tests/files/tests.py b/tests/files/tests.py
index b50061649a..1c005dde57 100644
--- a/tests/files/tests.py
+++ b/tests/files/tests.py
@@ -355,8 +355,9 @@ class FileMoveSafeTests(unittest.TestCase):
         handle_a, self.file_a = tempfile.mkstemp()
         handle_b, self.file_b = tempfile.mkstemp()
 
-        # file_move_safe should raise an IOError exception if destination file exists and allow_overwrite is False
-        with self.assertRaises(IOError):
+        # file_move_safe() raises OSError if the destination file exists and
+        # allow_overwrite is False.
+        with self.assertRaises(FileExistsError):
             file_move_safe(self.file_a, self.file_b, allow_overwrite=False)
 
         # should allow it and continue on if allow_overwrite is True
diff --git a/tests/i18n/tests.py b/tests/i18n/tests.py
index 2377c8992e..0f58789237 100644
--- a/tests/i18n/tests.py
+++ b/tests/i18n/tests.py
@@ -1747,13 +1747,10 @@ class TranslationFilesMissing(SimpleTestCase):
         gettext_module.find = lambda *args, **kw: None
 
     def test_failure_finding_default_mo_files(self):
-        '''
-        Ensure IOError is raised if the default language is unparseable.
-        Refs: #18192
-        '''
+        """OSError is raised if the default language is unparseable."""
         self.patchGettextFind()
         trans_real._translations = {}
-        with self.assertRaises(IOError):
+        with self.assertRaises(OSError):
             activate('en')
 
 
diff --git a/tests/mail/tests.py b/tests/mail/tests.py
index f06e053074..e283101b79 100644
--- a/tests/mail/tests.py
+++ b/tests/mail/tests.py
@@ -4,7 +4,6 @@ import mimetypes
 import os
 import shutil
 import smtpd
-import socket
 import sys
 import tempfile
 import threading
@@ -1570,7 +1569,7 @@ class SMTPBackendStoppedServerTests(SMTPBackendTestsBase):
         """
         A socket connection error is silenced with fail_silently=True.
         """
-        with self.assertRaises(socket.error):
+        with self.assertRaises(ConnectionError):
             self.backend.open()
         self.backend.fail_silently = True
         self.backend.open()
diff --git a/tests/requests/tests.py b/tests/requests/tests.py
index 720178a8b4..9391ca2a08 100644
--- a/tests/requests/tests.py
+++ b/tests/requests/tests.py
@@ -479,11 +479,11 @@ class RequestsTests(SimpleTestCase):
     def test_POST_connection_error(self):
         """
         If wsgi.input.read() raises an exception while trying to read() the
-        POST, the exception should be identifiable (not a generic IOError).
+        POST, the exception is identifiable (not a generic OSError).
         """
         class ExplodingBytesIO(BytesIO):
             def read(self, len=0):
-                raise IOError("kaboom!")
+                raise OSError('kaboom!')
 
         payload = b'name=value'
         request = WSGIRequest({
@@ -520,11 +520,11 @@ class RequestsTests(SimpleTestCase):
     def test_FILES_connection_error(self):
         """
         If wsgi.input.read() raises an exception while trying to read() the
-        FILES, the exception should be identifiable (not a generic IOError).
+        FILES, the exception is identifiable (not a generic OSError).
         """
         class ExplodingBytesIO(BytesIO):
             def read(self, len=0):
-                raise IOError("kaboom!")
+                raise OSError('kaboom!')
 
         payload = b'x'
         request = WSGIRequest({
diff --git a/tests/responses/tests.py b/tests/responses/tests.py
index 8adf092ca0..934e4dfe60 100644
--- a/tests/responses/tests.py
+++ b/tests/responses/tests.py
@@ -22,14 +22,14 @@ class HttpResponseBaseTests(SimpleTestCase):
         r = HttpResponseBase()
         self.assertIs(r.writable(), False)
 
-        with self.assertRaisesMessage(IOError, 'This HttpResponseBase instance is not writable'):
+        with self.assertRaisesMessage(OSError, 'This HttpResponseBase instance is not writable'):
             r.write('asdf')
-        with self.assertRaisesMessage(IOError, 'This HttpResponseBase instance is not writable'):
+        with self.assertRaisesMessage(OSError, 'This HttpResponseBase instance is not writable'):
             r.writelines(['asdf\n', 'qwer\n'])
 
     def test_tell(self):
         r = HttpResponseBase()
-        with self.assertRaisesMessage(IOError, 'This HttpResponseBase instance cannot tell its position'):
+        with self.assertRaisesMessage(OSError, 'This HttpResponseBase instance cannot tell its position'):
             r.tell()
 
     def test_setdefault(self):
diff --git a/tests/servers/tests.py b/tests/servers/tests.py
index 7f75b85d6c..1f111fb5ae 100644
--- a/tests/servers/tests.py
+++ b/tests/servers/tests.py
@@ -194,10 +194,10 @@ class LiveServerPort(LiveServerBase):
         TestCase = type("TestCase", (LiveServerBase,), {})
         try:
             TestCase.setUpClass()
-        except socket.error as e:
+        except OSError as e:
             if e.errno == errno.EADDRINUSE:
                 # We're out of ports, LiveServerTestCase correctly fails with
-                # a socket error.
+                # an OSError.
                 return
             # Unexpected error.
             raise
diff --git a/tests/sessions_tests/tests.py b/tests/sessions_tests/tests.py
index 733f5adb1d..0e8cb79fd5 100644
--- a/tests/sessions_tests/tests.py
+++ b/tests/sessions_tests/tests.py
@@ -532,7 +532,7 @@ class FileSessionTests(SessionTestsMixin, unittest.TestCase):
     def test_invalid_key_backslash(self):
         # Ensure we don't allow directory-traversal.
         # This is tested directly on _key_to_file, as load() will swallow
-        # a SuspiciousOperation in the same way as an IOError - by creating
+        # a SuspiciousOperation in the same way as an OSError - by creating
         # a new session, making it unclear whether the slashes were detected.
         with self.assertRaises(InvalidSessionKey):
             self.backend()._key_to_file("a\\b\\c")
diff --git a/tests/staticfiles_tests/cases.py b/tests/staticfiles_tests/cases.py
index ea746164a6..24de4e029e 100644
--- a/tests/staticfiles_tests/cases.py
+++ b/tests/staticfiles_tests/cases.py
@@ -23,7 +23,7 @@ class BaseStaticFilesMixin:
         )
 
     def assertFileNotFound(self, filepath):
-        with self.assertRaises(IOError):
+        with self.assertRaises(OSError):
             self._get_file(filepath)
 
     def render_template(self, template, **kwargs):
diff --git a/tests/template_tests/test_loaders.py b/tests/template_tests/test_loaders.py
index ea69472264..9023457751 100644
--- a/tests/template_tests/test_loaders.py
+++ b/tests/template_tests/test_loaders.py
@@ -191,11 +191,11 @@ class FileSystemLoaderTests(SimpleTestCase):
             tmppath = os.path.join(tmpdir, tmpfile.name)
             os.chmod(tmppath, 0o0222)
             with self.set_dirs([tmpdir]):
-                with self.assertRaisesMessage(IOError, 'Permission denied'):
+                with self.assertRaisesMessage(PermissionError, 'Permission denied'):
                     self.engine.get_template(tmpfile.name)
 
     def test_notafile_error(self):
-        with self.assertRaises(IOError):
+        with self.assertRaises(IsADirectoryError):
             self.engine.get_template('first')