unit tests for memorybased filelike objects stringio for unicode strings bytesio for bytes issue 24989 buffer overread issue 24989 buffer overread issue 24989 buffer overread test case for issue 6242 this will be caught by regrtest py r if this leak getnewargs is undefined on purpose this checks that pep 307 is used to provide pickling support pickle expects the class to be on the module level here we use a little hack to allow the pickletestmemio class to derive from self ioclass without having to define all combinations explicitly on the modulelevel we only support pickle protocol 2 and onward since we use extended reduce api of pep 307 to provide pickling support test pyio bytesio class also inherited for testing c implementation trying to change the size of the bytesio while a buffer is exported raises a buffererror mutating the buffer updates the bytesio after the buffer gets released we can resize and close the bytesio again trying to change the size of the bytesio while a buffer is exported raises a buffererror the c stringio decodes newlines in write calls but the python implementation only does when reading this function forces them to be decoded for testing these are just dummy values but we nevertheless check them for fear of unexpected breakage newlinenone newline newlinen newliner newlinern stringio can duplicate newlines in universal newlines mode these should not raise an error issue 20424 test if pickle restores properly the internal state of stringio this checks whether setstate does proper input validation various tests of copyonwrite behaviour for bytesio common code for all bytesio copyonwrite mutation tests ensure truncate causes a copy ensure write that would not cause a resize still results in a copy setstate should cause buffer to be released bytesio should accept only bytes for copyonwrite sharing since arbitrary bufferexporting objects like bytearray aren t guaranteed to be immutable xxx for the python version of io stringio this is highly dependent on the encoding used for the underlying buffer this checks whether setstate does proper input validation issue 24989 buffer overread issue 24989 buffer overread issue 24989 buffer overread test case for issue 6242 this will be caught by regrtest py r if this leak __getnewargs__ is undefined on purpose this checks that pep 307 is used to provide pickling support pickle expects the class to be on the module level here we use a little hack to allow the pickletestmemio class to derive from self ioclass without having to define all combinations explicitly on the module level we only support pickle protocol 2 and onward since we use extended __reduce__ api of pep 307 to provide pickling support test _pyio bytesio class also inherited for testing c implementation trying to change the size of the bytesio while a buffer is exported raises a buffererror mutating the buffer updates the bytesio after the buffer gets released we can resize and close the bytesio again trying to change the size of the bytesio while a buffer is exported raises a buffererror the c stringio decodes newlines in write calls but the python implementation only does when reading this function forces them to be decoded for testing these are just dummy values but we nevertheless check them for fear of unexpected breakage newline none newline newline n newline r newline r n stringio can duplicate newlines in universal newlines mode these should not raise an error issue 20424 test if pickle restores properly the internal state of stringio check if state 0 supports the buffer interface this checks whether __setstate__ does proper input validation use a variable to prevent constant folding various tests of copy on write behaviour for bytesio common code for all bytesio copy on write mutation tests ensure truncate causes a copy ensure write that would not cause a resize still results in a copy __setstate__ should cause buffer to be released bytesio should accept only bytes for copy on write sharing since arbitrary buffer exporting objects like bytearray aren t guaranteed to be immutable xxx for the python version of io stringio this is highly dependent on the encoding used for the underlying buffer this checks whether __setstate__ does proper input validation
import unittest
from test import support

import io
import _pyio as pyio
import pickle
import sys

class IntLike:
    def __init__(self, num):
        self._num = num
    def __index__(self):
        return self._num
    __int__ = __index__

class MemorySeekTestMixin:

    def testInit(self):
        buf = self.buftype("1234567890")
        bytesIo = self.ioclass(buf)

    def testRead(self):
        buf = self.buftype("1234567890")
        bytesIo = self.ioclass(buf)

        self.assertEqual(buf[:1], bytesIo.read(1))
        self.assertEqual(buf[1:5], bytesIo.read(4))
        self.assertEqual(buf[5:], bytesIo.read(900))
        self.assertEqual(self.EOF, bytesIo.read())

    def testReadNoArgs(self):
        buf = self.buftype("1234567890")
        bytesIo = self.ioclass(buf)

        self.assertEqual(buf, bytesIo.read())
        self.assertEqual(self.EOF, bytesIo.read())

    def testSeek(self):
        buf = self.buftype("1234567890")
        bytesIo = self.ioclass(buf)

        bytesIo.read(5)
        bytesIo.seek(0)
        self.assertEqual(buf, bytesIo.read())

        bytesIo.seek(3)
        self.assertEqual(buf[3:], bytesIo.read())
        self.assertRaises(TypeError, bytesIo.seek, 0.0)

    def testTell(self):
        buf = self.buftype("1234567890")
        bytesIo = self.ioclass(buf)

        self.assertEqual(0, bytesIo.tell())
        bytesIo.seek(5)
        self.assertEqual(5, bytesIo.tell())
        bytesIo.seek(10000)
        self.assertEqual(10000, bytesIo.tell())


class MemoryTestMixin:

    def test_detach(self):
        buf = self.ioclass()
        self.assertRaises(self.UnsupportedOperation, buf.detach)

    def write_ops(self, f, t):
        self.assertEqual(f.write(t("blah.")), 5)
        self.assertEqual(f.seek(0), 0)
        self.assertEqual(f.write(t("Hello.")), 6)
        self.assertEqual(f.tell(), 6)
        self.assertEqual(f.seek(5), 5)
        self.assertEqual(f.tell(), 5)
        self.assertEqual(f.write(t(" world\n\n\n")), 9)
        self.assertEqual(f.seek(0), 0)
        self.assertEqual(f.write(t("h")), 1)
        self.assertEqual(f.truncate(12), 12)
        self.assertEqual(f.tell(), 1)

    def test_write(self):
        buf = self.buftype("hello world\n")
        memio = self.ioclass(buf)

        self.write_ops(memio, self.buftype)
        self.assertEqual(memio.getvalue(), buf)
        memio = self.ioclass()
        self.write_ops(memio, self.buftype)
        self.assertEqual(memio.getvalue(), buf)
        self.assertRaises(TypeError, memio.write, None)
        memio.close()
        self.assertRaises(ValueError, memio.write, self.buftype(""))

    def test_writelines(self):
        buf = self.buftype("1234567890")
        memio = self.ioclass()

        self.assertEqual(memio.writelines([buf] * 100), None)
        self.assertEqual(memio.getvalue(), buf * 100)
        memio.writelines([])
        self.assertEqual(memio.getvalue(), buf * 100)
        memio = self.ioclass()
        self.assertRaises(TypeError, memio.writelines, [buf] + [1])
        self.assertEqual(memio.getvalue(), buf)
        self.assertRaises(TypeError, memio.writelines, None)
        memio.close()
        self.assertRaises(ValueError, memio.writelines, [])

    def test_writelines_error(self):
        memio = self.ioclass()
        def error_gen():
            yield self.buftype('spam')
            raise KeyboardInterrupt

        self.assertRaises(KeyboardInterrupt, memio.writelines, error_gen())

    def test_truncate(self):
        buf = self.buftype("1234567890")
        memio = self.ioclass(buf)

        self.assertRaises(ValueError, memio.truncate, -1)
        self.assertRaises(ValueError, memio.truncate, IntLike(-1))
        memio.seek(6)
        self.assertEqual(memio.truncate(IntLike(8)), 8)
        self.assertEqual(memio.getvalue(), buf[:8])
        self.assertEqual(memio.truncate(), 6)
        self.assertEqual(memio.getvalue(), buf[:6])
        self.assertEqual(memio.truncate(4), 4)
        self.assertEqual(memio.getvalue(), buf[:4])
        self.assertEqual(memio.tell(), 6)
        memio.seek(0, 2)
        memio.write(buf)
        self.assertEqual(memio.getvalue(), buf[:4] + buf)
        pos = memio.tell()
        self.assertEqual(memio.truncate(None), pos)
        self.assertEqual(memio.tell(), pos)
        self.assertRaises(TypeError, memio.truncate, '0')
        memio.close()
        self.assertRaises(ValueError, memio.truncate, 0)
        self.assertRaises(ValueError, memio.truncate, IntLike(0))

    def test_init(self):
        buf = self.buftype("1234567890")
        memio = self.ioclass(buf)
        self.assertEqual(memio.getvalue(), buf)
        memio = self.ioclass(None)
        self.assertEqual(memio.getvalue(), self.EOF)
        memio.__init__(buf * 2)
        self.assertEqual(memio.getvalue(), buf * 2)
        memio.__init__(buf)
        self.assertEqual(memio.getvalue(), buf)
        self.assertRaises(TypeError, memio.__init__, [])

    def test_read(self):
        buf = self.buftype("1234567890")
        memio = self.ioclass(buf)

        self.assertEqual(memio.read(0), self.EOF)
        self.assertEqual(memio.read(1), buf[:1])
        self.assertEqual(memio.read(4), buf[1:5])
        self.assertEqual(memio.read(900), buf[5:])
        self.assertEqual(memio.read(), self.EOF)
        memio.seek(0)
        self.assertEqual(memio.read(IntLike(0)), self.EOF)
        self.assertEqual(memio.read(IntLike(1)), buf[:1])
        self.assertEqual(memio.read(IntLike(4)), buf[1:5])
        self.assertEqual(memio.read(IntLike(900)), buf[5:])
        memio.seek(0)
        self.assertEqual(memio.read(), buf)
        self.assertEqual(memio.read(), self.EOF)
        self.assertEqual(memio.tell(), 10)
        memio.seek(0)
        self.assertEqual(memio.read(-1), buf)
        memio.seek(0)
        self.assertEqual(memio.read(IntLike(-1)), buf)
        memio.seek(0)
        self.assertEqual(type(memio.read()), type(buf))
        memio.seek(100)
        self.assertEqual(type(memio.read()), type(buf))
        memio.seek(0)
        self.assertEqual(memio.read(None), buf)
        self.assertRaises(TypeError, memio.read, '')
        memio.seek(len(buf) + 1)
        self.assertEqual(memio.read(1), self.EOF)
        memio.seek(len(buf) + 1)
        self.assertEqual(memio.read(IntLike(1)), self.EOF)
        memio.seek(len(buf) + 1)
        self.assertEqual(memio.read(), self.EOF)
        memio.close()
        self.assertRaises(ValueError, memio.read)

    def test_readline(self):
        buf = self.buftype("1234567890\n")
        memio = self.ioclass(buf * 2)

        self.assertEqual(memio.readline(0), self.EOF)
        self.assertEqual(memio.readline(IntLike(0)), self.EOF)
        self.assertEqual(memio.readline(), buf)
        self.assertEqual(memio.readline(), buf)
        self.assertEqual(memio.readline(), self.EOF)
        memio.seek(0)
        self.assertEqual(memio.readline(5), buf[:5])
        self.assertEqual(memio.readline(5), buf[5:10])
        self.assertEqual(memio.readline(5), buf[10:15])
        memio.seek(0)
        self.assertEqual(memio.readline(IntLike(5)), buf[:5])
        self.assertEqual(memio.readline(IntLike(5)), buf[5:10])
        self.assertEqual(memio.readline(IntLike(5)), buf[10:15])
        memio.seek(0)
        self.assertEqual(memio.readline(-1), buf)
        memio.seek(0)
        self.assertEqual(memio.readline(IntLike(-1)), buf)
        memio.seek(0)
        self.assertEqual(memio.readline(0), self.EOF)
        self.assertEqual(memio.readline(IntLike(0)), self.EOF)
        
        memio.seek(len(buf) * 2 + 1)
        self.assertEqual(memio.readline(), self.EOF)

        buf = self.buftype("1234567890\n")
        memio = self.ioclass((buf * 3)[:-1])
        self.assertEqual(memio.readline(), buf)
        self.assertEqual(memio.readline(), buf)
        self.assertEqual(memio.readline(), buf[:-1])
        self.assertEqual(memio.readline(), self.EOF)
        memio.seek(0)
        self.assertEqual(type(memio.readline()), type(buf))
        self.assertEqual(memio.readline(), buf)
        self.assertRaises(TypeError, memio.readline, '')
        memio.close()
        self.assertRaises(ValueError,  memio.readline)

    def test_readlines(self):
        buf = self.buftype("1234567890\n")
        memio = self.ioclass(buf * 10)

        self.assertEqual(memio.readlines(), [buf] * 10)
        memio.seek(5)
        self.assertEqual(memio.readlines(), [buf[5:]] + [buf] * 9)
        memio.seek(0)
        self.assertEqual(memio.readlines(15), [buf] * 2)
        memio.seek(0)
        self.assertEqual(memio.readlines(-1), [buf] * 10)
        memio.seek(0)
        self.assertEqual(memio.readlines(0), [buf] * 10)
        memio.seek(0)
        self.assertEqual(type(memio.readlines()[0]), type(buf))
        memio.seek(0)
        self.assertEqual(memio.readlines(None), [buf] * 10)
        self.assertRaises(TypeError, memio.readlines, '')
        
        memio.seek(len(buf) * 10 + 1)
        self.assertEqual(memio.readlines(), [])
        memio.close()
        self.assertRaises(ValueError, memio.readlines)

    def test_iterator(self):
        buf = self.buftype("1234567890\n")
        memio = self.ioclass(buf * 10)

        self.assertEqual(iter(memio), memio)
        self.assertTrue(hasattr(memio, '__iter__'))
        self.assertTrue(hasattr(memio, '__next__'))
        i = 0
        for line in memio:
            self.assertEqual(line, buf)
            i += 1
        self.assertEqual(i, 10)
        memio.seek(0)
        i = 0
        for line in memio:
            self.assertEqual(line, buf)
            i += 1
        self.assertEqual(i, 10)
        
        memio.seek(len(buf) * 10 + 1)
        self.assertEqual(list(memio), [])
        memio = self.ioclass(buf * 2)
        memio.close()
        self.assertRaises(ValueError, memio.__next__)

    def test_getvalue(self):
        buf = self.buftype("1234567890")
        memio = self.ioclass(buf)

        self.assertEqual(memio.getvalue(), buf)
        memio.read()
        self.assertEqual(memio.getvalue(), buf)
        self.assertEqual(type(memio.getvalue()), type(buf))
        memio = self.ioclass(buf * 1000)
        self.assertEqual(memio.getvalue()[-3:], self.buftype("890"))
        memio = self.ioclass(buf)
        memio.close()
        self.assertRaises(ValueError, memio.getvalue)

    def test_seek(self):
        buf = self.buftype("1234567890")
        memio = self.ioclass(buf)

        memio.read(5)
        self.assertRaises(ValueError, memio.seek, -1)
        self.assertRaises(ValueError, memio.seek, 1, -1)
        self.assertRaises(ValueError, memio.seek, 1, 3)
        self.assertEqual(memio.seek(0), 0)
        self.assertEqual(memio.seek(0, 0), 0)
        self.assertEqual(memio.read(), buf)
        self.assertEqual(memio.seek(3), 3)
        self.assertEqual(memio.seek(0, 1), 3)
        self.assertEqual(memio.read(), buf[3:])
        self.assertEqual(memio.seek(len(buf)), len(buf))
        self.assertEqual(memio.read(), self.EOF)
        memio.seek(len(buf) + 1)
        self.assertEqual(memio.read(), self.EOF)
        self.assertEqual(memio.seek(0, 2), len(buf))
        self.assertEqual(memio.read(), self.EOF)
        memio.close()
        self.assertRaises(ValueError, memio.seek, 0)

    def test_overseek(self):
        buf = self.buftype("1234567890")
        memio = self.ioclass(buf)

        self.assertEqual(memio.seek(len(buf) + 1), 11)
        self.assertEqual(memio.read(), self.EOF)
        self.assertEqual(memio.tell(), 11)
        self.assertEqual(memio.getvalue(), buf)
        memio.write(self.EOF)
        self.assertEqual(memio.getvalue(), buf)
        memio.write(buf)
        self.assertEqual(memio.getvalue(), buf + self.buftype('\0') + buf)

    def test_tell(self):
        buf = self.buftype("1234567890")
        memio = self.ioclass(buf)

        self.assertEqual(memio.tell(), 0)
        memio.seek(5)
        self.assertEqual(memio.tell(), 5)
        memio.seek(10000)
        self.assertEqual(memio.tell(), 10000)
        memio.close()
        self.assertRaises(ValueError, memio.tell)

    def test_flush(self):
        buf = self.buftype("1234567890")
        memio = self.ioclass(buf)

        self.assertEqual(memio.flush(), None)

    def test_flags(self):
        memio = self.ioclass()

        self.assertEqual(memio.writable(), True)
        self.assertEqual(memio.readable(), True)
        self.assertEqual(memio.seekable(), True)
        self.assertEqual(memio.isatty(), False)
        self.assertEqual(memio.closed, False)
        memio.close()
        self.assertRaises(ValueError, memio.writable)
        self.assertRaises(ValueError, memio.readable)
        self.assertRaises(ValueError, memio.seekable)
        self.assertRaises(ValueError, memio.isatty)
        self.assertEqual(memio.closed, True)

    def test_subclassing(self):
        buf = self.buftype("1234567890")
        def test1():
            class MemIO(self.ioclass):
                pass
            m = MemIO(buf)
            return m.getvalue()
        def test2():
            class MemIO(self.ioclass):
                def __init__(me, a, b):
                    self.ioclass.__init__(me, a)
            m = MemIO(buf, None)
            return m.getvalue()
        self.assertEqual(test1(), buf)
        self.assertEqual(test2(), buf)

    def test_instance_dict_leak(self):
        
        
        for _ in range(100):
            memio = self.ioclass()
            memio.foo = 1

    def test_pickling(self):
        buf = self.buftype("1234567890")
        memio = self.ioclass(buf)
        memio.foo = 42
        memio.seek(2)

        class PickleTestMemIO(self.ioclass):
            def __init__(me, initvalue, foo):
                self.ioclass.__init__(me, initvalue)
                me.foo = foo
            
            

        
        
        
        
        import __main__
        PickleTestMemIO.__module__ = '__main__'
        PickleTestMemIO.__qualname__ = PickleTestMemIO.__name__
        __main__.PickleTestMemIO = PickleTestMemIO
        submemio = PickleTestMemIO(buf, 80)
        submemio.seek(2)

        
        
        for proto in range(2, pickle.HIGHEST_PROTOCOL + 1):
            for obj in (memio, submemio):
                obj2 = pickle.loads(pickle.dumps(obj, protocol=proto))
                self.assertEqual(obj.getvalue(), obj2.getvalue())
                self.assertEqual(obj.__class__, obj2.__class__)
                self.assertEqual(obj.foo, obj2.foo)
                self.assertEqual(obj.tell(), obj2.tell())
                obj2.close()
                self.assertRaises(ValueError, pickle.dumps, obj2, proto)
        del __main__.PickleTestMemIO


class PyBytesIOTest(MemoryTestMixin, MemorySeekTestMixin, unittest.TestCase):
    

    UnsupportedOperation = pyio.UnsupportedOperation

    @staticmethod
    def buftype(s):
        return s.encode("ascii")
    ioclass = pyio.BytesIO
    EOF = b""

    def test_getbuffer(self):
        memio = self.ioclass(b"1234567890")
        buf = memio.getbuffer()
        self.assertEqual(bytes(buf), b"1234567890")
        memio.seek(5)
        buf = memio.getbuffer()
        self.assertEqual(bytes(buf), b"1234567890")
        
        
        self.assertRaises(BufferError, memio.write, b'x' * 100)
        self.assertRaises(BufferError, memio.truncate)
        self.assertRaises(BufferError, memio.close)
        self.assertFalse(memio.closed)
        
        buf[3:6] = b"abc"
        self.assertEqual(bytes(buf), b"123abc7890")
        self.assertEqual(memio.getvalue(), b"123abc7890")
        
        
        del buf
        support.gc_collect()
        memio.truncate()
        memio.close()
        self.assertRaises(ValueError, memio.getbuffer)

    def test_getbuffer_empty(self):
        memio = self.ioclass()
        buf = memio.getbuffer()
        self.assertEqual(bytes(buf), b"")
        
        
        self.assertRaises(BufferError, memio.write, b'x')
        buf2 = memio.getbuffer()
        self.assertRaises(BufferError, memio.write, b'x')
        buf.release()
        self.assertRaises(BufferError, memio.write, b'x')
        buf2.release()
        memio.write(b'x')

    def test_read1(self):
        buf = self.buftype("1234567890")
        self.assertEqual(self.ioclass(buf).read1(), buf)
        self.assertEqual(self.ioclass(buf).read1(-1), buf)

    def test_readinto(self):
        buf = self.buftype("1234567890")
        memio = self.ioclass(buf)

        b = bytearray(b"hello")
        self.assertEqual(memio.readinto(b), 5)
        self.assertEqual(b, b"12345")
        self.assertEqual(memio.readinto(b), 5)
        self.assertEqual(b, b"67890")
        self.assertEqual(memio.readinto(b), 0)
        self.assertEqual(b, b"67890")
        b = bytearray(b"hello world")
        memio.seek(0)
        self.assertEqual(memio.readinto(b), 10)
        self.assertEqual(b, b"1234567890d")
        b = bytearray(b"")
        memio.seek(0)
        self.assertEqual(memio.readinto(b), 0)
        self.assertEqual(b, b"")
        self.assertRaises(TypeError, memio.readinto, '')
        import array
        a = array.array('b', b"hello world")
        memio = self.ioclass(buf)
        memio.readinto(a)
        self.assertEqual(a.tobytes(), b"1234567890d")
        memio.close()
        self.assertRaises(ValueError, memio.readinto, b)
        memio = self.ioclass(b"123")
        b = bytearray()
        memio.seek(42)
        memio.readinto(b)
        self.assertEqual(b, b"")

    def test_relative_seek(self):
        buf = self.buftype("1234567890")
        memio = self.ioclass(buf)

        self.assertEqual(memio.seek(-1, 1), 0)
        self.assertEqual(memio.seek(3, 1), 3)
        self.assertEqual(memio.seek(-4, 1), 0)
        self.assertEqual(memio.seek(-1, 2), 9)
        self.assertEqual(memio.seek(1, 1), 10)
        self.assertEqual(memio.seek(1, 2), 11)
        memio.seek(-3, 2)
        self.assertEqual(memio.read(), buf[-3:])
        memio.seek(0)
        memio.seek(1, 1)
        self.assertEqual(memio.read(), buf[1:])

    def test_unicode(self):
        memio = self.ioclass()

        self.assertRaises(TypeError, self.ioclass, "1234567890")
        self.assertRaises(TypeError, memio.write, "1234567890")
        self.assertRaises(TypeError, memio.writelines, ["1234567890"])

    def test_bytes_array(self):
        buf = b"1234567890"
        import array
        a = array.array('b', list(buf))
        memio = self.ioclass(a)
        self.assertEqual(memio.getvalue(), buf)
        self.assertEqual(memio.write(a), 10)
        self.assertEqual(memio.getvalue(), buf)

    def test_issue5449(self):
        buf = self.buftype("1234567890")
        self.ioclass(initial_bytes=buf)
        self.assertRaises(TypeError, self.ioclass, buf, foo=None)


class TextIOTestMixin:

    def test_newlines_property(self):
        memio = self.ioclass(newline=None)
        
        
        
        def force_decode():
            memio.seek(0)
            memio.read()
        self.assertEqual(memio.newlines, None)
        memio.write("a\n")
        force_decode()
        self.assertEqual(memio.newlines, "\n")
        memio.write("b\r\n")
        force_decode()
        self.assertEqual(memio.newlines, ("\n", "\r\n"))
        memio.write("c\rd")
        force_decode()
        self.assertEqual(memio.newlines, ("\r", "\n", "\r\n"))

    def test_relative_seek(self):
        memio = self.ioclass()

        self.assertRaises(OSError, memio.seek, -1, 1)
        self.assertRaises(OSError, memio.seek, 3, 1)
        self.assertRaises(OSError, memio.seek, -3, 1)
        self.assertRaises(OSError, memio.seek, -1, 2)
        self.assertRaises(OSError, memio.seek, 1, 1)
        self.assertRaises(OSError, memio.seek, 1, 2)

    def test_textio_properties(self):
        memio = self.ioclass()

        
        
        self.assertIsNone(memio.encoding)
        self.assertIsNone(memio.errors)
        self.assertFalse(memio.line_buffering)

    def test_newline_default(self):
        memio = self.ioclass("a\nb\r\nc\rd")
        self.assertEqual(list(memio), ["a\n", "b\r\n", "c\rd"])
        self.assertEqual(memio.getvalue(), "a\nb\r\nc\rd")

        memio = self.ioclass()
        self.assertEqual(memio.write("a\nb\r\nc\rd"), 8)
        memio.seek(0)
        self.assertEqual(list(memio), ["a\n", "b\r\n", "c\rd"])
        self.assertEqual(memio.getvalue(), "a\nb\r\nc\rd")

    def test_newline_none(self):
        
        memio = self.ioclass("a\nb\r\nc\rd", newline=None)
        self.assertEqual(list(memio), ["a\n", "b\n", "c\n", "d"])
        memio.seek(0)
        self.assertEqual(memio.read(1), "a")
        self.assertEqual(memio.read(2), "\nb")
        self.assertEqual(memio.read(2), "\nc")
        self.assertEqual(memio.read(1), "\n")
        self.assertEqual(memio.getvalue(), "a\nb\nc\nd")

        memio = self.ioclass(newline=None)
        self.assertEqual(2, memio.write("a\n"))
        self.assertEqual(3, memio.write("b\r\n"))
        self.assertEqual(3, memio.write("c\rd"))
        memio.seek(0)
        self.assertEqual(memio.read(), "a\nb\nc\nd")
        self.assertEqual(memio.getvalue(), "a\nb\nc\nd")

        memio = self.ioclass("a\r\nb", newline=None)
        self.assertEqual(memio.read(3), "a\nb")

    def test_newline_empty(self):
        
        memio = self.ioclass("a\nb\r\nc\rd", newline="")
        self.assertEqual(list(memio), ["a\n", "b\r\n", "c\r", "d"])
        memio.seek(0)
        self.assertEqual(memio.read(4), "a\nb\r")
        self.assertEqual(memio.read(2), "\nc")
        self.assertEqual(memio.read(1), "\r")
        self.assertEqual(memio.getvalue(), "a\nb\r\nc\rd")

        memio = self.ioclass(newline="")
        self.assertEqual(2, memio.write("a\n"))
        self.assertEqual(2, memio.write("b\r"))
        self.assertEqual(2, memio.write("\nc"))
        self.assertEqual(2, memio.write("\rd"))
        memio.seek(0)
        self.assertEqual(list(memio), ["a\n", "b\r\n", "c\r", "d"])
        self.assertEqual(memio.getvalue(), "a\nb\r\nc\rd")

    def test_newline_lf(self):
        
        memio = self.ioclass("a\nb\r\nc\rd", newline="\n")
        self.assertEqual(list(memio), ["a\n", "b\r\n", "c\rd"])
        self.assertEqual(memio.getvalue(), "a\nb\r\nc\rd")

        memio = self.ioclass(newline="\n")
        self.assertEqual(memio.write("a\nb\r\nc\rd"), 8)
        memio.seek(0)
        self.assertEqual(list(memio), ["a\n", "b\r\n", "c\rd"])
        self.assertEqual(memio.getvalue(), "a\nb\r\nc\rd")

    def test_newline_cr(self):
        
        memio = self.ioclass("a\nb\r\nc\rd", newline="\r")
        self.assertEqual(memio.read(), "a\rb\r\rc\rd")
        memio.seek(0)
        self.assertEqual(list(memio), ["a\r", "b\r", "\r", "c\r", "d"])
        self.assertEqual(memio.getvalue(), "a\rb\r\rc\rd")

        memio = self.ioclass(newline="\r")
        self.assertEqual(memio.write("a\nb\r\nc\rd"), 8)
        memio.seek(0)
        self.assertEqual(list(memio), ["a\r", "b\r", "\r", "c\r", "d"])
        memio.seek(0)
        self.assertEqual(memio.readlines(), ["a\r", "b\r", "\r", "c\r", "d"])
        self.assertEqual(memio.getvalue(), "a\rb\r\rc\rd")

    def test_newline_crlf(self):
        
        memio = self.ioclass("a\nb\r\nc\rd", newline="\r\n")
        self.assertEqual(memio.read(), "a\r\nb\r\r\nc\rd")
        memio.seek(0)
        self.assertEqual(list(memio), ["a\r\n", "b\r\r\n", "c\rd"])
        memio.seek(0)
        self.assertEqual(memio.readlines(), ["a\r\n", "b\r\r\n", "c\rd"])
        self.assertEqual(memio.getvalue(), "a\r\nb\r\r\nc\rd")

        memio = self.ioclass(newline="\r\n")
        self.assertEqual(memio.write("a\nb\r\nc\rd"), 8)
        memio.seek(0)
        self.assertEqual(list(memio), ["a\r\n", "b\r\r\n", "c\rd"])
        self.assertEqual(memio.getvalue(), "a\r\nb\r\r\nc\rd")

    def test_issue5265(self):
        
        memio = self.ioclass("a\r\nb\r\n", newline=None)
        self.assertEqual(memio.read(5), "a\nb\n")
        self.assertEqual(memio.getvalue(), "a\nb\n")

    def test_newline_argument(self):
        self.assertRaises(TypeError, self.ioclass, newline=b"\n")
        self.assertRaises(ValueError, self.ioclass, newline="error")
        
        for newline in (None, "", "\n", "\r", "\r\n"):
            self.ioclass(newline=newline)


class PyStringIOTest(MemoryTestMixin, MemorySeekTestMixin,
                     TextIOTestMixin, unittest.TestCase):
    buftype = str
    ioclass = pyio.StringIO
    UnsupportedOperation = pyio.UnsupportedOperation
    EOF = ""

    def test_lone_surrogates(self):
        
        memio = self.ioclass('\ud800')
        self.assertEqual(memio.read(), '\ud800')

        memio = self.ioclass()
        memio.write('\ud800')
        self.assertEqual(memio.getvalue(), '\ud800')


class PyStringIOPickleTest(TextIOTestMixin, unittest.TestCase):
    
    buftype = str
    UnsupportedOperation = pyio.UnsupportedOperation
    EOF = ""

    class ioclass(pyio.StringIO):
        def __new__(cls, *args, **kwargs):
            return pickle.loads(pickle.dumps(pyio.StringIO(*args, **kwargs)))
        def __init__(self, *args, **kwargs):
            pass


class CBytesIOTest(PyBytesIOTest):
    ioclass = io.BytesIO
    UnsupportedOperation = io.UnsupportedOperation

    def test_getstate(self):
        memio = self.ioclass()
        state = memio.__getstate__()
        self.assertEqual(len(state), 3)
        bytearray(state[0]) 
        self.assertIsInstance(state[1], int)
        if state[2] is not None:
            self.assertIsInstance(state[2], dict)
        memio.close()
        self.assertRaises(ValueError, memio.__getstate__)

    def test_setstate(self):
        
        memio = self.ioclass()
        memio.__setstate__((b"no error", 0, None))
        memio.__setstate__((bytearray(b"no error"), 0, None))
        memio.__setstate__((b"no error", 0, {'spam': 3}))
        self.assertRaises(ValueError, memio.__setstate__, (b"", -1, None))
        self.assertRaises(TypeError, memio.__setstate__, ("unicode", 0, None))
        self.assertRaises(TypeError, memio.__setstate__, (b"", 0.0, None))
        self.assertRaises(TypeError, memio.__setstate__, (b"", 0, 0))
        self.assertRaises(TypeError, memio.__setstate__, (b"len-test", 0))
        self.assertRaises(TypeError, memio.__setstate__)
        self.assertRaises(TypeError, memio.__setstate__, 0)
        memio.close()
        self.assertRaises(ValueError, memio.__setstate__, (b"closed", 0, None))

    check_sizeof = support.check_sizeof

    @support.cpython_only
    def test_sizeof(self):
        basesize = support.calcobjsize('P2n2Pn')
        check = self.check_sizeof
        self.assertEqual(object.__sizeof__(io.BytesIO()), basesize)
        check(io.BytesIO(), basesize )
        n = 1000  
        check(io.BytesIO(b'a' * n), basesize + sys.getsizeof(b'a' * n))

    

    def _test_cow_mutation(self, mutation):
        
        imm = b' ' * 1024
        old_rc = sys.getrefcount(imm)
        memio = self.ioclass(imm)
        self.assertEqual(sys.getrefcount(imm), old_rc + 1)
        mutation(memio)
        self.assertEqual(sys.getrefcount(imm), old_rc)

    @support.cpython_only
    def test_cow_truncate(self):
        
        def mutation(memio):
            memio.truncate(1)
        self._test_cow_mutation(mutation)

    @support.cpython_only
    def test_cow_write(self):
        
        def mutation(memio):
            memio.seek(0)
            memio.write(b'foo')
        self._test_cow_mutation(mutation)

    @support.cpython_only
    def test_cow_setstate(self):
        
        memio = self.ioclass(b'foooooo')
        state = memio.__getstate__()
        def mutation(memio):
            memio.__setstate__(state)
        self._test_cow_mutation(mutation)

    @support.cpython_only
    def test_cow_mutable(self):
        
        
        
        ba = bytearray(1024)
        old_rc = sys.getrefcount(ba)
        memio = self.ioclass(ba)
        self.assertEqual(sys.getrefcount(ba), old_rc)

class CStringIOTest(PyStringIOTest):
    ioclass = io.StringIO
    UnsupportedOperation = io.UnsupportedOperation

    
    
    def test_widechar(self):
        buf = self.buftype("\U0002030a\U00020347")
        memio = self.ioclass(buf)

        self.assertEqual(memio.getvalue(), buf)
        self.assertEqual(memio.write(buf), len(buf))
        self.assertEqual(memio.tell(), len(buf))
        self.assertEqual(memio.getvalue(), buf)
        self.assertEqual(memio.write(buf), len(buf))
        self.assertEqual(memio.tell(), len(buf) * 2)
        self.assertEqual(memio.getvalue(), buf + buf)

    def test_getstate(self):
        memio = self.ioclass()
        state = memio.__getstate__()
        self.assertEqual(len(state), 4)
        self.assertIsInstance(state[0], str)
        self.assertIsInstance(state[1], str)
        self.assertIsInstance(state[2], int)
        if state[3] is not None:
            self.assertIsInstance(state[3], dict)
        memio.close()
        self.assertRaises(ValueError, memio.__getstate__)

    def test_setstate(self):
        
        memio = self.ioclass()
        memio.__setstate__(("no error", "\n", 0, None))
        memio.__setstate__(("no error", "", 0, {'spam': 3}))
        self.assertRaises(ValueError, memio.__setstate__, ("", "f", 0, None))
        self.assertRaises(ValueError, memio.__setstate__, ("", "", -1, None))
        self.assertRaises(TypeError, memio.__setstate__, (b"", "", 0, None))
        self.assertRaises(TypeError, memio.__setstate__, ("", b"", 0, None))
        self.assertRaises(TypeError, memio.__setstate__, ("", "", 0.0, None))
        self.assertRaises(TypeError, memio.__setstate__, ("", "", 0, 0))
        self.assertRaises(TypeError, memio.__setstate__, ("len-test", 0))
        self.assertRaises(TypeError, memio.__setstate__)
        self.assertRaises(TypeError, memio.__setstate__, 0)
        memio.close()
        self.assertRaises(ValueError, memio.__setstate__, ("closed", "", 0, None))


class CStringIOPickleTest(PyStringIOPickleTest):
    UnsupportedOperation = io.UnsupportedOperation

    class ioclass(io.StringIO):
        def __new__(cls, *args, **kwargs):
            return pickle.loads(pickle.dumps(io.StringIO(*args, **kwargs)))
        def __init__(self, *args, **kwargs):
            pass


if __name__ == '__main__':
    unittest.main()