Python test.support.check_warnings() Examples

def test_opening_mode(self):
        try:
            # invalid mode, should raise ValueError
            fi = FileInput(mode="w")
            self.fail("FileInput should reject invalid mode argument")
        except ValueError:
            pass
        t1 = None
        try:
            # try opening in universal newline mode
            t1 = writeTmp(1, [b"A\nB\r\nC\rD"], mode="wb")
            with check_warnings(('', DeprecationWarning)):
                fi = FileInput(files=t1, mode="U")
            with check_warnings(('', DeprecationWarning)):
                lines = list(fi)
            self.assertEqual(lines, ["A\n", "B\n", "C\n", "D"])
        finally:
            remove_tempfiles(t1) 

def test_change_cwd__non_existent_dir__quiet_true(self):
        """Test passing a non-existent directory with quiet=True."""
        original_cwd = os.getcwd()

        with support.temp_dir() as parent_dir:
            bad_dir = os.path.join(parent_dir, 'does_not_exist')
            with support.check_warnings() as recorder:
                with support.change_cwd(bad_dir, quiet=True) as new_cwd:
                    self.assertEqual(new_cwd, original_cwd)
                    self.assertEqual(os.getcwd(), new_cwd)
                warnings = [str(w.message) for w in recorder.warnings]

        expected = ['tests may fail, unable to change CWD to: ' + bad_dir]
        self.assertEqual(warnings, expected)

    # Tests for change_cwd() 

def test_garbage_collection(self):
        # C TextIOWrapper objects are collected, and collecting them flushes
        # all data to disk.
        # The Python version has __del__, so it ends in gc.garbage instead.
        with support.check_warnings(('', ResourceWarning)):
            rawio = io.FileIO(support.TESTFN, "wb")
            b = self.BufferedWriter(rawio)
            t = self.TextIOWrapper(b, encoding="ascii")
            t.write("456def")
            t.x = t
            wr = weakref.ref(t)
            del t
            support.gc_collect()
        self.assertIsNone(wr(), wr)
        with self.open(support.TESTFN, "rb") as f:
            self.assertEqual(f.read(), b"456def") 

def test_destructor(self):
        record = []
        class MyFileIO(self.FileIO):
            def __del__(self):
                record.append(1)
                try:
                    f = super().__del__
                except AttributeError:
                    pass
                else:
                    f()
            def close(self):
                record.append(2)
                super().close()
            def flush(self):
                record.append(3)
                super().flush()
        with support.check_warnings(('', ResourceWarning)):
            f = MyFileIO(support.TESTFN, "wb")
            f.write(b"xxx")
            del f
            support.gc_collect()
            self.assertEqual(record, [1, 2, 3])
            with self.open(support.TESTFN, "rb") as f:
                self.assertEqual(f.read(), b"xxx") 

def test_temp_dir__existing_dir__quiet_true(self):
        """Test passing a directory that already exists with quiet=True."""
        path = tempfile.mkdtemp()
        path = os.path.realpath(path)

        try:
            with support.check_warnings() as recorder:
                with support.temp_dir(path, quiet=True) as temp_path:
                    self.assertEqual(path, temp_path)
                warnings = [str(w.message) for w in recorder.warnings]
            # Make sure temp_dir did not delete the original directory.
            self.assertTrue(os.path.isdir(path))
        finally:
            shutil.rmtree(path)

        expected = ['tests may fail, unable to create temp dir: ' + path]
        self.assertEqual(warnings, expected) 

def test_destructor(self):
        record = []
        class MyFileIO(self.FileIO):
            def __del__(self):
                record.append(1)
                try:
                    f = super().__del__
                except AttributeError:
                    pass
                else:
                    f()
            def close(self):
                record.append(2)
                super().close()
            def flush(self):
                record.append(3)
                super().flush()
        with support.check_warnings(('', ResourceWarning)):
            f = MyFileIO(support.TESTFN, "wb")
            f.write(b"xxx")
            del f
            support.gc_collect()
            self.assertEqual(record, [1, 2, 3])
            with self.open(support.TESTFN, "rb") as f:
                self.assertEqual(f.read(), b"xxx") 

def test_garbage_collection(self):
        # C TextIOWrapper objects are collected, and collecting them flushes
        # all data to disk.
        # The Python version has __del__, so it ends in gc.garbage instead.
        with support.check_warnings(('', ResourceWarning)):
            rawio = io.FileIO(support.TESTFN, "wb")
            b = self.BufferedWriter(rawio)
            t = self.TextIOWrapper(b, encoding="ascii")
            t.write("456def")
            t.x = t
            wr = weakref.ref(t)
            del t
            support.gc_collect()
        self.assertIsNone(wr(), wr)
        with self.open(support.TESTFN, "rb") as f:
            self.assertEqual(f.read(), b"456def") 

def test_exec(self):
        g = {}
        exec('z = 1', g)
        if '__builtins__' in g:
            del g['__builtins__']
        self.assertEqual(g, {'z': 1})

        exec('z = 1+1', g)
        if '__builtins__' in g:
            del g['__builtins__']
        self.assertEqual(g, {'z': 2})
        g = {}
        l = {}

        with check_warnings():
            warnings.filterwarnings("ignore", "global statement",
                    module="<string>")
            exec('global a; a = 1; b = 2', g, l)
        if '__builtins__' in g:
            del g['__builtins__']
        if '__builtins__' in l:
            del l['__builtins__']
        self.assertEqual((g, l), ({'a': 1}, {'b': 2})) 

def test_temp_dir__existing_dir__quiet_true(self):
        """Test passing a directory that already exists with quiet=True."""
        path = tempfile.mkdtemp()
        path = os.path.realpath(path)

        try:
            with support.check_warnings() as recorder:
                with support.temp_dir(path, quiet=True) as temp_path:
                    self.assertEqual(path, temp_path)
                warnings = [str(w.message) for w in recorder.warnings]
            # Make sure temp_dir did not delete the original directory.
            self.assertTrue(os.path.isdir(path))
        finally:
            shutil.rmtree(path)

        expected = ['tests may fail, unable to create temp dir: ' + path]
        self.assertEqual(warnings, expected)

    # Tests for change_cwd() 

def test_splitunc(self):
        with self.assertWarns(DeprecationWarning):
            ntpath.splitunc('')
        with support.check_warnings(('', DeprecationWarning)):
            tester('ntpath.splitunc("c:\\foo\\bar")',
                   ('', 'c:\\foo\\bar'))
            tester('ntpath.splitunc("c:/foo/bar")',
                   ('', 'c:/foo/bar'))
            tester('ntpath.splitunc("\\\\conky\\mountpoint\\foo\\bar")',
                   ('\\\\conky\\mountpoint', '\\foo\\bar'))
            tester('ntpath.splitunc("//conky/mountpoint/foo/bar")',
                   ('//conky/mountpoint', '/foo/bar'))
            tester('ntpath.splitunc("\\\\\\conky\\mountpoint\\foo\\bar")',
                   ('', '\\\\\\conky\\mountpoint\\foo\\bar'))
            tester('ntpath.splitunc("///conky/mountpoint/foo/bar")',
                   ('', '///conky/mountpoint/foo/bar'))
            tester('ntpath.splitunc("\\\\conky\\\\mountpoint\\foo\\bar")',
                   ('', '\\\\conky\\\\mountpoint\\foo\\bar'))
            tester('ntpath.splitunc("//conky//mountpoint/foo/bar")',
                   ('', '//conky//mountpoint/foo/bar'))
            self.assertEqual(ntpath.splitunc('//conky/MOUNTPOİNT/foo/bar'),
                             ('//conky/MOUNTPOİNT', '/foo/bar')) 

def urlopen(url, data=None, proxies=None):
    """urlopen(url [, data]) -> open file-like object"""
    global _urlopener
    if proxies is not None:
        opener = urllib.request.FancyURLopener(proxies=proxies)
    elif not _urlopener:
        with support.check_warnings(
                ('FancyURLopener style of invoking requests is deprecated.',
                DeprecationWarning)):
            opener = urllib.request.FancyURLopener()
        _urlopener = opener
    else:
        opener = _urlopener
    if data is None:
        return opener.open(url)
    else:
        return opener.open(url, data) 

def test_resize(self):
        for length in range(1, 100, 7):
            # generate a fresh string (refcount=1)
            text = 'a' * length + 'b'

            with support.check_warnings(('unicode_internal codec has been '
                                         'deprecated', DeprecationWarning)):
                # fill wstr internal field
                abc = text.encode('unicode_internal')
                self.assertEqual(abc.decode('unicode_internal'), text)

                # resize text: wstr field must be cleared and then recomputed
                text += 'c'
                abcdef = text.encode('unicode_internal')
                self.assertNotEqual(abc, abcdef)
                self.assertEqual(abcdef.decode('unicode_internal'), text) 

def test_relpath_errors(self):
        # Check relpath() raises friendly TypeErrors.
        with support.check_warnings(('', (BytesWarning, DeprecationWarning)),
                                    quiet=True):
            errmsg = "Can't mix strings and bytes in path components"
            with self.assertRaisesRegex(TypeError, errmsg):
                self.pathmodule.relpath(b'bytes', 'str')
            with self.assertRaisesRegex(TypeError, errmsg):
                self.pathmodule.relpath('str', b'bytes')
            errmsg = r'relpath\(\) argument must be str or bytes, not %r'
            with self.assertRaisesRegex(TypeError, errmsg % 'int'):
                self.pathmodule.relpath(42, 'str')
            with self.assertRaisesRegex(TypeError, errmsg % 'int'):
                self.pathmodule.relpath('str', 42)
            with self.assertRaisesRegex(TypeError, errmsg % 'bytearray'):
                self.pathmodule.relpath(bytearray(b'foo'), bytearray(b'bar')) 

def test_join_errors(self):
        # Check join() raises friendly TypeErrors.
        with support.check_warnings(('', BytesWarning), quiet=True):
            errmsg = "Can't mix strings and bytes in path components"
            with self.assertRaisesRegex(TypeError, errmsg):
                self.pathmodule.join(b'bytes', 'str')
            with self.assertRaisesRegex(TypeError, errmsg):
                self.pathmodule.join('str', b'bytes')
            # regression, see #15377
            errmsg = r'join\(\) argument must be str or bytes, not %r'
            with self.assertRaisesRegex(TypeError, errmsg % 'int'):
                self.pathmodule.join(42, 'str')
            with self.assertRaisesRegex(TypeError, errmsg % 'int'):
                self.pathmodule.join('str', 42)
            with self.assertRaisesRegex(TypeError, errmsg % 'int'):
                self.pathmodule.join(42)
            with self.assertRaisesRegex(TypeError, errmsg % 'list'):
                self.pathmodule.join([])
            with self.assertRaisesRegex(TypeError, errmsg % 'bytearray'):
                self.pathmodule.join(bytearray(b'foo'), bytearray(b'bar')) 

def __init__(self, quiet=False):
        if sys.flags.optimize >= 2:
            # under -OO, doctests cannot be run and therefore not all warnings
            # will be emitted
            quiet = True
        deprecations = (
            # Search behaviour is broken if search path starts with "/".
            ("This search is broken in 1.3 and earlier, and will be fixed "
             "in a future version.  If you rely on the current behaviour, "
             "change it to '.+'", FutureWarning),
            # Element.getchildren() and Element.getiterator() are deprecated.
            ("This method will be removed in future versions.  "
             "Use .+ instead.", DeprecationWarning),
            ("This method will be removed in future versions.  "
             "Use .+ instead.", PendingDeprecationWarning))
        self.checkwarnings = support.check_warnings(*deprecations, quiet=quiet) 

def assertOldResultWarning(self, test, failures):
        with support.check_warnings(("TestResult has no add.+ method,",
                                     RuntimeWarning)):
            result = OldResult()
            test.run(result)
            self.assertEqual(len(result.failures), failures) 

def test_deprecated_parse_qs(self):
        # this func is moved to urllib.parse, this is just a sanity check
        with check_warnings(('cgi.parse_qs is deprecated, use urllib.parse.'
                             'parse_qs instead', DeprecationWarning)):
            self.assertEqual({'a': ['A1'], 'B': ['B3'], 'b': ['B2']},
                             cgi.parse_qs('a=A1&b=B2&B=B3')) 

def test_iter_importers_avoids_emulation(self):
        with check_warnings() as w:
            for importer in pkgutil.iter_importers(): pass
            self.assertEqual(len(w.warnings), 0) 

def test_get_importer_avoids_emulation(self):
        # We use an illegal path so *none* of the path hooks should fire
        with check_warnings() as w:
            self.assertIsNone(pkgutil.get_importer("*??"))
            self.assertEqual(len(w.warnings), 0) 

def test_find_loader_avoids_emulation(self):
        with check_warnings() as w:
            self.assertIsNotNone(pkgutil.find_loader("sys"))
            self.assertIsNotNone(pkgutil.find_loader("os"))
            self.assertIsNotNone(pkgutil.find_loader("test.support"))
            self.assertEqual(len(w.warnings), 0) 

def test_compress_deprecated(self):
        tmpdir =  self._create_files()
        base_name = os.path.join(self.mkdtemp(), 'archive')

        # using compress and testing the PendingDeprecationWarning
        old_dir = os.getcwd()
        os.chdir(tmpdir)
        try:
            with check_warnings() as w:
                warnings.simplefilter("always")
                make_tarball(base_name, 'dist', compress='compress')
        finally:
            os.chdir(old_dir)
        tarball = base_name + '.tar.Z'
        self.assertTrue(os.path.exists(tarball))
        self.assertEqual(len(w.warnings), 1)

        # same test with dry_run
        os.remove(tarball)
        old_dir = os.getcwd()
        os.chdir(tmpdir)
        try:
            with check_warnings() as w:
                warnings.simplefilter("always")
                make_tarball(base_name, 'dist', compress='compress',
                             dry_run=True)
        finally:
            os.chdir(old_dir)
        self.assertFalse(os.path.exists(tarball))
        self.assertEqual(len(w.warnings), 1) 

def test_get_loader_handles_missing_loader_attribute(self):
        global __loader__
        this_loader = __loader__
        del __loader__
        try:
            with check_warnings() as w:
                self.assertIsNotNone(pkgutil.get_loader(__name__))
                self.assertEqual(len(w.warnings), 0)
        finally:
            __loader__ = this_loader 

def check_deprecated(self):
        return check_warnings(
            ("This emulation is deprecated, use 'importlib' instead",
             DeprecationWarning)) 

def testWarnings(self):
        with check_warnings(quiet=True) as w:
            self.assertEqual(w.warnings, [])
            self.assertRaises(TypeError, self.FileIO, [])
            self.assertEqual(w.warnings, [])
            self.assertRaises(ValueError, self.FileIO, "/some/invalid/name", "rt")
            self.assertEqual(w.warnings, []) 

def test_bad_encode_args(self):
        for encoding in all_unicode_encodings:
            encoder = codecs.getencoder(encoding)
            with support.check_warnings():
                # unicode-internal has been deprecated
                self.assertRaises(TypeError, encoder) 

def test_encode_length(self):
        with support.check_warnings(('unicode_internal codec has been '
                                     'deprecated', DeprecationWarning)):
            # Issue 3739
            encoder = codecs.getencoder("unicode_internal")
            self.assertEqual(encoder("a")[1], 1)
            self.assertEqual(encoder("\xe9\u0142")[1], 2)

            self.assertEqual(codecs.escape_encode(br'\x00')[1], 4)

# From http://www.gnu.org/software/libidn/draft-josefsson-idn-test-vectors.html 

def test_decode_error_attributes(self):
        try:
            with support.check_warnings(('unicode_internal codec has been '
                                         'deprecated', DeprecationWarning)):
                b"\x00\x00\x00\x00\x00\x11\x11\x00".decode("unicode_internal")
        except UnicodeDecodeError as ex:
            self.assertEqual("unicode_internal", ex.encoding)
            self.assertEqual(b"\x00\x00\x00\x00\x00\x11\x11\x00", ex.object)
            self.assertEqual(4, ex.start)
            self.assertEqual(8, ex.end)
        else:
            self.fail() 

def test_bug691291(self):
        # Files are always opened in binary mode, even if no binary mode was
        # specified.  This means that no automatic conversion of '\n' is done
        # on reading and writing.
        s1 = 'Hello\r\nworld\r\n'

        s = s1.encode(self.encoding)
        self.addCleanup(support.unlink, support.TESTFN)
        with open(support.TESTFN, 'wb') as fp:
            fp.write(s)
        with support.check_warnings(('', DeprecationWarning)):
            reader = codecs.open(support.TESTFN, 'U', encoding=self.encoding)
        with reader:
            self.assertEqual(reader.read(), s1) 

def test_check_warnings(self):
        # Explicit tests for the test.support convenience wrapper
        wmod = self.module
        if wmod is not sys.modules['warnings']:
            self.skipTest('module to test is not loaded warnings module')
        with support.check_warnings(quiet=False) as w:
            self.assertEqual(w.warnings, [])
            wmod.simplefilter("always")
            wmod.warn("foo")
            self.assertEqual(str(w.message), "foo")
            wmod.warn("bar")
            self.assertEqual(str(w.message), "bar")
            self.assertEqual(str(w.warnings[0].message), "foo")
            self.assertEqual(str(w.warnings[1].message), "bar")
            w.reset()
            self.assertEqual(w.warnings, [])

        with support.check_warnings():
            # defaults to quiet=True without argument
            pass
        with support.check_warnings(('foo', UserWarning)):
            wmod.warn("foo")

        with self.assertRaises(AssertionError):
            with support.check_warnings(('', RuntimeWarning)):
                # defaults to quiet=False with argument
                pass
        with self.assertRaises(AssertionError):
            with support.check_warnings(('foo', RuntimeWarning)):
                wmod.warn("foo") 

def test_storlines(self):
        f = io.BytesIO(RETR_DATA.replace('\r\n', '\n').encode('ascii'))
        self.client.storlines('stor', f)
        self.check_data(self.server.handler_instance.last_received_data, RETR_DATA)
        # test new callback arg
        flag = []
        f.seek(0)
        self.client.storlines('stor foo', f, callback=lambda x: flag.append(None))
        self.assertTrue(flag)

        f = io.StringIO(RETR_DATA.replace('\r\n', '\n'))
        # storlines() expects a binary file, not a text file
        with support.check_warnings(('', BytesWarning), quiet=True):
            self.assertRaises(TypeError, self.client.storlines, 'stor foo', f)