diff --git a/Lib/_sitebuiltins.py b/Lib/_sitebuiltins.py
index c29cf4b..c66269a 100644
--- a/Lib/_sitebuiltins.py
+++ b/Lib/_sitebuiltins.py
@@ -47,7 +47,7 @@ def __setup(self):
         data = None
         for filename in self.__filenames:
             try:
-                with open(filename, "r") as fp:
+                with open(filename, encoding='utf-8') as fp:
                     data = fp.read()
                 break
             except OSError:
diff --git a/Lib/logging/__init__.py b/Lib/logging/__init__.py
index 411aa53..555f598 100644
--- a/Lib/logging/__init__.py
+++ b/Lib/logging/__init__.py
@@ -1150,6 +1150,8 @@ def __init__(self, filename, mode='a', encoding=None, delay=False, errors=None):
         self.baseFilename = os.path.abspath(filename)
         self.mode = mode
         self.encoding = encoding
+        if "b" not in mode:
+            self.encoding = io.text_encoding(encoding)
         self.errors = errors
         self.delay = delay
         # bpo-26789: FileHandler keeps a reference to the builtin open()
@@ -2022,8 +2024,10 @@ def basicConfig(**kwargs):
                 filename = kwargs.pop("filename", None)
                 mode = kwargs.pop("filemode", 'a')
                 if filename:
-                    if 'b'in mode:
+                    if 'b' in mode:
                         errors = None
+                    else:
+                        encoding = io.text_encoding(encoding)
                     h = FileHandler(filename, mode,
                                     encoding=encoding, errors=errors)
                 else:
diff --git a/Lib/logging/handlers.py b/Lib/logging/handlers.py
index 867ef4e..b0d5885 100644
--- a/Lib/logging/handlers.py
+++ b/Lib/logging/handlers.py
@@ -23,7 +23,7 @@
 To use, simply 'import logging.handlers' and log away!
 """
 
-import logging, socket, os, pickle, struct, time, re
+import io, logging, socket, os, pickle, struct, time, re
 from stat import ST_DEV, ST_INO, ST_MTIME
 import queue
 import threading
@@ -150,6 +150,8 @@ def __init__(self, filename, mode='a', maxBytes=0, backupCount=0,
         # on each run.
         if maxBytes > 0:
             mode = 'a'
+        if "b" not in mode:
+            encoding = io.text_encoding(encoding)
         BaseRotatingHandler.__init__(self, filename, mode, encoding=encoding,
                                      delay=delay, errors=errors)
         self.maxBytes = maxBytes
@@ -205,6 +207,7 @@ class TimedRotatingFileHandler(BaseRotatingHandler):
     def __init__(self, filename, when='h', interval=1, backupCount=0,
                  encoding=None, delay=False, utc=False, atTime=None,
                  errors=None):
+        encoding = io.text_encoding(encoding)
         BaseRotatingHandler.__init__(self, filename, 'a', encoding=encoding,
                                      delay=delay, errors=errors)
         self.when = when.upper()
@@ -442,6 +445,8 @@ class WatchedFileHandler(logging.FileHandler):
     """
     def __init__(self, filename, mode='a', encoding=None, delay=False,
                  errors=None):
+        if "b" not in mode:
+            encoding = io.text_encoding(encoding)
         logging.FileHandler.__init__(self, filename, mode=mode,
                                      encoding=encoding, delay=delay,
                                      errors=errors)
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index 72feaed..35ad0b9 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -363,7 +363,7 @@ class GetSourceBase(unittest.TestCase):
     fodderModule = None
 
     def setUp(self):
-        with open(inspect.getsourcefile(self.fodderModule)) as fp:
+        with open(inspect.getsourcefile(self.fodderModule), encoding="utf-8") as fp:
             self.source = fp.read()
 
     def sourcerange(self, top, bottom):
@@ -773,8 +773,8 @@ class TestNoEOL(GetSourceBase):
     def setUp(self):
         self.tempdir = TESTFN + '_dir'
         os.mkdir(self.tempdir)
-        with open(os.path.join(self.tempdir,
-                               'inspect_fodder3%spy' % os.extsep), 'w') as f:
+        with open(os.path.join(self.tempdir, 'inspect_fodder3%spy' % os.extsep),
+                  'w', encoding='utf-8') as f:
             f.write("class X:\n    pass # No EOL")
         with DirsOnSysPath(self.tempdir):
             import inspect_fodder3 as mod3
@@ -1805,7 +1805,7 @@ def test_no_dict_no_slots(self):
 
     def test_no_dict_no_slots_instance_member(self):
         # returns descriptor
-        with open(__file__) as handle:
+        with open(__file__, encoding='utf-8') as handle:
             self.assertEqual(inspect.getattr_static(handle, 'name'), type(handle).name)
 
     def test_inherited_slots(self):
@@ -4045,7 +4045,7 @@ def foo():
 
     def assertInspectEqual(self, path, source):
         inspected_src = inspect.getsource(source)
-        with open(path) as src:
+        with open(path, encoding='utf-8') as src:
             self.assertEqual(
                 src.read().splitlines(True),
                 inspected_src.splitlines(True)
@@ -4056,7 +4056,7 @@ def test_getsource_reload(self):
         with _ready_to_import('reload_bug', self.src_before) as (name, path):
             module = importlib.import_module(name)
             self.assertInspectEqual(path, module)
-            with open(path, 'w') as src:
+            with open(path, 'w', encoding='utf-8') as src:
                 src.write(self.src_after)
             self.assertInspectEqual(path, module)
 
diff --git a/Lib/test/test_interpreters.py b/Lib/test/test_interpreters.py
index 8d44d49..6266aa7 100644
--- a/Lib/test/test_interpreters.py
+++ b/Lib/test/test_interpreters.py
@@ -14,11 +14,11 @@ def _captured_script(script):
     indented = script.replace('\n', '\n                ')
     wrapped = dedent(f"""
         import contextlib
-        with open({w}, 'w') as spipe:
+        with open({w}, 'w', encoding='utf-8') as spipe:
             with contextlib.redirect_stdout(spipe):
                 {indented}
         """)
-    return wrapped, open(r)
+    return wrapped, open(r, encoding='utf-8')
 
 
 def clean_up_interpreters():
@@ -411,7 +411,7 @@ def f():
     def test_fork(self):
         interp = interpreters.create()
         import tempfile
-        with tempfile.NamedTemporaryFile('w+') as file:
+        with tempfile.NamedTemporaryFile('w+', encoding='utf-8') as file:
             file.write('')
             file.flush()
 
@@ -421,7 +421,7 @@ def test_fork(self):
                 try:
                     os.fork()
                 except RuntimeError:
-                    with open('{file.name}', 'w') as out:
+                    with open('{file.name}', 'w', encoding='utf-8') as out:
                         out.write('{expected}')
                 """)
             interp.run(script)
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index d493b19..48a3cca 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -2601,8 +2601,8 @@ def test_constructor(self):
         self.assertEqual(t.encoding, "utf-8")
         self.assertEqual(t.line_buffering, True)
         self.assertEqual("\xe9\n", t.readline())
-        self.assertRaises(TypeError, t.__init__, b, newline=42)
-        self.assertRaises(ValueError, t.__init__, b, newline='xyzzy')
+        self.assertRaises(TypeError, t.__init__, b, encoding="utf-8", newline=42)
+        self.assertRaises(ValueError, t.__init__, b, encoding="utf-8", newline='xyzzy')
 
     def test_uninitialized(self):
         t = self.TextIOWrapper.__new__(self.TextIOWrapper)
@@ -3732,7 +3732,7 @@ def test_initialization(self):
         r = self.BytesIO(b"\xc3\xa9\n\n")
         b = self.BufferedReader(r, 1000)
         t = self.TextIOWrapper(b, encoding="utf-8")
-        self.assertRaises(ValueError, t.__init__, b, newline='xyzzy')
+        self.assertRaises(ValueError, t.__init__, b, encoding="utf-8", newline='xyzzy')
         self.assertRaises(ValueError, t.read)
 
         t = self.TextIOWrapper.__new__(self.TextIOWrapper)
diff --git a/Lib/test/test_iter.py b/Lib/test/test_iter.py
index a7658b5..20cb9c0 100644
--- a/Lib/test/test_iter.py
+++ b/Lib/test/test_iter.py
@@ -337,13 +337,13 @@ def test_iter_dict(self):
 
     # Test a file
     def test_iter_file(self):
-        f = open(TESTFN, "w")
+        f = open(TESTFN, "w", encoding="utf-8")
         try:
             for i in range(5):
                 f.write("%d\n" % i)
         finally:
             f.close()
-        f = open(TESTFN, "r")
+        f = open(TESTFN, "r", encoding="utf-8")
         try:
             self.check_for_loop(f, ["0\n", "1\n", "2\n", "3\n", "4\n"], pickle=False)
             self.check_for_loop(f, [], pickle=False)
@@ -366,13 +366,13 @@ def test_builtin_list(self):
         self.assertRaises(TypeError, list, list)
         self.assertRaises(TypeError, list, 42)
 
-        f = open(TESTFN, "w")
+        f = open(TESTFN, "w", encoding="utf-8")
         try:
             for i in range(5):
                 f.write("%d\n" % i)
         finally:
             f.close()
-        f = open(TESTFN, "r")
+        f = open(TESTFN, "r", encoding="utf-8")
         try:
             self.assertEqual(list(f), ["0\n", "1\n", "2\n", "3\n", "4\n"])
             f.seek(0, 0)
@@ -399,13 +399,13 @@ def test_builtin_tuple(self):
         self.assertRaises(TypeError, tuple, list)
         self.assertRaises(TypeError, tuple, 42)
 
-        f = open(TESTFN, "w")
+        f = open(TESTFN, "w", encoding="utf-8")
         try:
             for i in range(5):
                 f.write("%d\n" % i)
         finally:
             f.close()
-        f = open(TESTFN, "r")
+        f = open(TESTFN, "r", encoding="utf-8")
         try:
             self.assertEqual(tuple(f), ("0\n", "1\n", "2\n", "3\n", "4\n"))
             f.seek(0, 0)
@@ -476,14 +476,14 @@ def test_builtin_max_min(self):
         self.assertEqual(max(d.values()), 3)
         self.assertEqual(min(iter(d.values())), 1)
 
-        f = open(TESTFN, "w")
+        f = open(TESTFN, "w", encoding="utf-8")
         try:
             f.write("medium line\n")
             f.write("xtra large line\n")
             f.write("itty-bitty line\n")
         finally:
             f.close()
-        f = open(TESTFN, "r")
+        f = open(TESTFN, "r", encoding="utf-8")
         try:
             self.assertEqual(min(f), "itty-bitty line\n")
             f.seek(0, 0)
@@ -509,13 +509,13 @@ def test_builtin_map(self):
                      i < len(d) and dkeys[i] or None)
                     for i in range(3)]
 
-        f = open(TESTFN, "w")
+        f = open(TESTFN, "w", encoding="utf-8")
         try:
             for i in range(10):
                 f.write("xy" * i + "\n") # line i has len 2*i+1
         finally:
             f.close()
-        f = open(TESTFN, "r")
+        f = open(TESTFN, "r", encoding="utf-8")
         try:
             self.assertEqual(list(map(len, f)), list(range(1, 21, 2)))
         finally:
@@ -556,12 +556,12 @@ def __next__(self):
                 self.i = i+1
                 return i
 
-        f = open(TESTFN, "w")
+        f = open(TESTFN, "w", encoding="utf-8")
         try:
             f.write("a\n" "bbb\n" "cc\n")
         finally:
             f.close()
-        f = open(TESTFN, "r")
+        f = open(TESTFN, "r", encoding="utf-8")
         try:
             self.assertEqual(list(zip(IntsFrom(0), f, IntsFrom(-100))),
                              [(0, "a\n", -100),
@@ -624,13 +624,13 @@ def __next__(self):
                     return "fooled you!"
                 return next(self.it)
 
-        f = open(TESTFN, "w")
+        f = open(TESTFN, "w", encoding="utf-8")
         try:
             f.write("a\n" + "b\n" + "c\n")
         finally:
             f.close()
 
-        f = open(TESTFN, "r")
+        f = open(TESTFN, "r", encoding="utf-8")
         # Nasty:  string.join(s) can't know whether unicode.join() is needed
         # until it's seen all of s's elements.  But in this case, f's
         # iterator cannot be restarted.  So what we're testing here is
@@ -676,12 +676,12 @@ def test_in_and_not_in(self):
             self.assertIn((k, v), d.items())
             self.assertNotIn((v, k), d.items())
 
-        f = open(TESTFN, "w")
+        f = open(TESTFN, "w", encoding="utf-8")
         try:
             f.write("a\n" "b\n" "c\n")
         finally:
             f.close()
-        f = open(TESTFN, "r")
+        f = open(TESTFN, "r", encoding="utf-8")
         try:
             for chunk in "abc":
                 f.seek(0, 0)
@@ -713,12 +713,12 @@ def test_countOf(self):
         self.assertEqual(countOf(d.values(), 2j), 1)
         self.assertEqual(countOf(d.values(), 1j), 0)
 
-        f = open(TESTFN, "w")
+        f = open(TESTFN, "w", encoding="utf-8")
         try:
             f.write("a\n" "b\n" "c\n" "b\n")
         finally:
             f.close()
-        f = open(TESTFN, "r")
+        f = open(TESTFN, "r", encoding="utf-8")
         try:
             for letter, count in ("a", 1), ("b", 2), ("c", 1), ("d", 0):
                 f.seek(0, 0)
@@ -748,12 +748,12 @@ def test_indexOf(self):
         self.assertRaises(TypeError, indexOf, indexOf, indexOf)
         self.assertRaises(ZeroDivisionError, indexOf, BadIterableClass(), 1)
 
-        f = open(TESTFN, "w")
+        f = open(TESTFN, "w", encoding="utf-8")
         try:
             f.write("a\n" "b\n" "c\n" "d\n" "e\n")
         finally:
             f.close()
-        f = open(TESTFN, "r")
+        f = open(TESTFN, "r", encoding="utf-8")
         try:
             fiter = iter(f)
             self.assertEqual(indexOf(fiter, "b\n"), 1)
@@ -774,7 +774,7 @@ def test_indexOf(self):
 
     # Test iterators with file.writelines().
     def test_writelines(self):
-        f = open(TESTFN, "w")
+        f = open(TESTFN, "w", encoding="utf-8")
 
         try:
             self.assertRaises(TypeError, f.writelines, None)
@@ -813,7 +813,7 @@ def __iter__(self):
             f.writelines(Whatever(6, 6+2000))
             f.close()
 
-            f = open(TESTFN)
+            f = open(TESTFN, encoding="utf-8")
             expected = [str(i) + "\n" for i in range(1, 2006)]
             self.assertEqual(list(f), expected)
 
@@ -857,14 +857,14 @@ def test_unpack_iter(self):
         a, b, c = {1: 42, 2: 42, 3: 42}.values()
         self.assertEqual((a, b, c), (42, 42, 42))
 
-        f = open(TESTFN, "w")
+        f = open(TESTFN, "w", encoding="utf-8")
         lines = ("a\n", "bb\n", "ccc\n")
         try:
             for line in lines:
                 f.write(line)
         finally:
             f.close()
-        f = open(TESTFN, "r")
+        f = open(TESTFN, "r", encoding="utf-8")
         try:
             a, b, c = f
             self.assertEqual((a, b, c), lines)
diff --git a/Lib/test/test_json/test_tool.py b/Lib/test/test_json/test_tool.py
index 5411188..0386690 100644
--- a/Lib/test/test_json/test_tool.py
+++ b/Lib/test/test_json/test_tool.py
@@ -125,7 +125,7 @@ def test_infile_outfile(self):
         outfile = os_helper.TESTFN + '.out'
         rc, out, err = assert_python_ok('-m', 'json.tool', infile, outfile)
         self.addCleanup(os.remove, outfile)
-        with open(outfile, "r") as fp:
+        with open(outfile, "r", encoding="utf-8") as fp:
             self.assertEqual(fp.read(), self.expect)
         self.assertEqual(rc, 0)
         self.assertEqual(out, b'')
diff --git a/Lib/test/test_linecache.py b/Lib/test/test_linecache.py
index cfc6ba8..59e00da 100644
--- a/Lib/test/test_linecache.py
+++ b/Lib/test/test_linecache.py
@@ -116,7 +116,7 @@ def test_getline(self):
         # Check module loading
         for entry in MODULES:
             filename = os.path.join(MODULE_PATH, entry) + '.py'
-            with open(filename) as file:
+            with open(filename, encoding='utf-8') as file:
                 for index, line in enumerate(file):
                     self.assertEqual(line, getline(filename, index + 1))
 
@@ -126,7 +126,7 @@ def test_getline(self):
 
     def test_no_ending_newline(self):
         self.addCleanup(os_helper.unlink, os_helper.TESTFN)
-        with open(os_helper.TESTFN, "w") as fp:
+        with open(os_helper.TESTFN, "w", encoding='utf-8') as fp:
             fp.write(SOURCE_3)
         lines = linecache.getlines(os_helper.TESTFN)
         self.assertEqual(lines, ["\n", "def f():\n", "    return 3\n"])
@@ -153,18 +153,18 @@ def test_checkcache(self):
         # Create a source file and cache its contents
         source_name = os_helper.TESTFN + '.py'
         self.addCleanup(os_helper.unlink, source_name)
-        with open(source_name, 'w') as source:
+        with open(source_name, 'w', encoding='utf-8') as source:
             source.write(SOURCE_1)
         getline(source_name, 1)
 
         # Keep a copy of the old contents
         source_list = []
-        with open(source_name) as source:
+        with open(source_name, encoding='utf-8') as source:
             for index, line in enumerate(source):
                 self.assertEqual(line, getline(source_name, index + 1))
                 source_list.append(line)
 
-        with open(source_name, 'w') as source:
+        with open(source_name, 'w', encoding='utf-8') as source:
             source.write(SOURCE_2)
 
         # Try to update a bogus cache entry
@@ -176,7 +176,7 @@ def test_checkcache(self):
 
         # Update the cache and check whether it matches the new source file
         linecache.checkcache(source_name)
-        with open(source_name) as source:
+        with open(source_name, encoding='utf-8') as source:
             for index, line in enumerate(source):
                 self.assertEqual(line, getline(source_name, index + 1))
                 source_list.append(line)
diff --git a/Lib/test/test_lltrace.py b/Lib/test/test_lltrace.py
index 5f7d564..8f1a92e 100644
--- a/Lib/test/test_lltrace.py
+++ b/Lib/test/test_lltrace.py
@@ -13,7 +13,7 @@ def test_lltrace_does_not_crash_on_subscript_operator(self):
         # bpo-34113. The crash happened at the command line console of
         # debug Python builds with __ltrace__ enabled (only possible in console),
         # when the interal Python stack was negatively adjusted
-        with open(os_helper.TESTFN, 'w') as fd:
+        with open(os_helper.TESTFN, 'w', encoding='utf-8') as fd:
             self.addCleanup(os_helper.unlink, os_helper.TESTFN)
             fd.write(textwrap.dedent("""\
             import code
diff --git a/Lib/test/test_logging.py b/Lib/test/test_logging.py
index 859baa4..452ba78 100644
--- a/Lib/test/test_logging.py
+++ b/Lib/test/test_logging.py
@@ -553,7 +553,7 @@ def test_builtin_handlers(self):
                 os.close(fd)
                 if not existing:
                     os.unlink(fn)
-                h = logging.handlers.WatchedFileHandler(fn, delay=True)
+                h = logging.handlers.WatchedFileHandler(fn, encoding='utf-8', delay=True)
                 if existing:
                     dev, ino = h.dev, h.ino
                     self.assertEqual(dev, -1)
@@ -616,7 +616,7 @@ def test_path_objects(self):
         if sys.platform in ('linux', 'darwin'):
             cases += ((logging.handlers.WatchedFileHandler, (pfn, 'w')),)
         for cls, args in cases:
-            h = cls(*args)
+            h = cls(*args, encoding="utf-8")
             self.assertTrue(os.path.exists(fn))
             h.close()
             os.unlink(fn)
@@ -645,7 +645,7 @@ def remove_loop(fname, tries):
             remover = threading.Thread(target=remove_loop, args=(fn, del_count))
             remover.daemon = True
             remover.start()
-            h = logging.handlers.WatchedFileHandler(fn, delay=delay)
+            h = logging.handlers.WatchedFileHandler(fn, encoding='utf-8', delay=delay)
             f = logging.Formatter('%(asctime)s: %(levelname)s: %(message)s')
             h.setFormatter(f)
             try:
@@ -677,7 +677,7 @@ class _OurHandler(logging.Handler):
             def __init__(self):
                 super().__init__()
                 self.sub_handler = logging.StreamHandler(
-                    stream=open('/dev/null', 'wt'))
+                    stream=open('/dev/null', 'wt', encoding='utf-8'))
 
             def emit(self, record):
                 self.sub_handler.acquire()
@@ -4355,7 +4355,7 @@ def __del__(self):
             # basicConfig() opens the file, but logging.shutdown() closes
             # it at Python exit. When A.__del__() is called,
             # FileHandler._open() must be called again to re-open the file.
-            logging.basicConfig(filename={filename!r})
+            logging.basicConfig(filename={filename!r}, encoding="utf-8")
 
             a = A()
 
@@ -4365,7 +4365,7 @@ def __del__(self):
         """)
         assert_python_ok("-c", code)
 
-        with open(filename) as fp:
+        with open(filename, encoding="utf-8") as fp:
             self.assertEqual(fp.read().rstrip(), "ERROR:root:log in __del__")
 
     def test_recursion_error(self):
@@ -4557,13 +4557,13 @@ def cleanup(h1, h2, fn):
             h2.close()
             os.remove(fn)
 
-        logging.basicConfig(filename='test.log')
+        logging.basicConfig(filename='test.log', encoding='utf-8')
 
         self.assertEqual(len(logging.root.handlers), 1)
         handler = logging.root.handlers[0]
         self.assertIsInstance(handler, logging.FileHandler)
 
-        expected = logging.FileHandler('test.log', 'a')
+        expected = logging.FileHandler('test.log', 'a', encoding='utf-8')
         self.assertEqual(handler.stream.mode, expected.stream.mode)
         self.assertEqual(handler.stream.name, expected.stream.name)
         self.addCleanup(cleanup, handler, expected, 'test.log')
@@ -5161,7 +5161,7 @@ def assertLogFile(self, filename):
 class FileHandlerTest(BaseFileTest):
     def test_delay(self):
         os.unlink(self.fn)
-        fh = logging.FileHandler(self.fn, delay=True)
+        fh = logging.FileHandler(self.fn, encoding='utf-8', delay=True)
         self.assertIsNone(fh.stream)
         self.assertFalse(os.path.exists(self.fn))
         fh.handle(logging.makeLogRecord({}))
@@ -5176,19 +5176,20 @@ def next_rec(self):
 
     def test_should_not_rollover(self):
         # If maxbytes is zero rollover never occurs
-        rh = logging.handlers.RotatingFileHandler(self.fn, maxBytes=0)
+        rh = logging.handlers.RotatingFileHandler(
+                self.fn, encoding="utf-8", maxBytes=0)
         self.assertFalse(rh.shouldRollover(None))
         rh.close()
 
     def test_should_rollover(self):
-        rh = logging.handlers.RotatingFileHandler(self.fn, maxBytes=1)
+        rh = logging.handlers.RotatingFileHandler(self.fn, encoding="utf-8", maxBytes=1)
         self.assertTrue(rh.shouldRollover(self.next_rec()))
         rh.close()
 
     def test_file_created(self):
         # checks that the file is created and assumes it was created
         # by us
-        rh = logging.handlers.RotatingFileHandler(self.fn)
+        rh = logging.handlers.RotatingFileHandler(self.fn, encoding="utf-8")
         rh.emit(self.next_rec())
         self.assertLogFile(self.fn)
         rh.close()
@@ -5197,7 +5198,7 @@ def test_rollover_filenames(self):
         def namer(name):
             return name + ".test"
         rh = logging.handlers.RotatingFileHandler(
-            self.fn, backupCount=2, maxBytes=1)
+            self.fn, encoding="utf-8", backupCount=2, maxBytes=1)
         rh.namer = namer
         rh.emit(self.next_rec())
         self.assertLogFile(self.fn)
@@ -5218,7 +5219,7 @@ def rotator(self, source, dest):
                     os.rename(source, dest + ".rotated")
 
         rh = HandlerWithNamerAndRotator(
-            self.fn, backupCount=2, maxBytes=1)
+            self.fn, encoding="utf-8", backupCount=2, maxBytes=1)
         self.assertEqual(rh.namer(self.fn), self.fn + ".test")
         rh.emit(self.next_rec())
         self.assertLogFile(self.fn)
@@ -5241,7 +5242,7 @@ def rotator(source, dest):
             os.remove(source)
 
         rh = logging.handlers.RotatingFileHandler(
-            self.fn, backupCount=2, maxBytes=1)
+            self.fn, encoding="utf-8", backupCount=2, maxBytes=1)
         rh.rotator = rotator
         rh.namer = namer
         m1 = self.next_rec()