def test_tell_and_seek_from_end_unbounded_substream(self):
s = Substream(io.BytesIO(b"0123456789"), 3, None)
self.assertEqual(0, s.tell())
self.assertEqual(5, s.seek(-2, io.SEEK_END))
self.assertEqual(5, s.tell())
self.assertEqual(b"89", s.read(2))
def test_tell_and_seek_from_end(self):
s = Substream(io.BytesIO(b"0123456789"), 3, 6)
self.assertEqual(0, s.tell())
self.assertEqual(2, s.seek(-1, io.SEEK_END))
self.assertEqual(2, s.tell())
self.assertEqual(b"5", s.read(2))
def test_tell_and_seek_from_cur(self):
s = Substream(io.BytesIO(b"0123456789"), 3, 6)
self.assertEqual(0, s.tell())
self.assertEqual(b"34", s.read(2))
self.assertEqual(1, s.seek(-1, io.SEEK_CUR))
self.assertEqual(1, s.tell())
self.assertEqual(b"45", s.read(2))
def test_tell_and_seek_set(self):
s = Substream(io.BytesIO(b"0123456789"), 3, 6)
self.assertEqual(0, s.tell())
self.assertEqual(1, s.seek(1))
self.assertEqual(b"4", s.read(1))
self.assertEqual(2, s.tell())
self.assertEqual(b"5", s.read(2))
self.assertEqual(b"", s.read(2))
def test_tell_and_seek_set_unseekable(self):
s = Substream(UnseekableStream(io.BytesIO(b"012")), 3, 6)
self.assertEqual(0, s.tell())
with self.assertRaises(OSError):
self.assertEqual(1, s.seek(1))
self.assertEqual(b"0", s.read(1))
self.assertEqual(1, s.tell())
self.assertEqual(b"12", s.read(2))
self.assertEqual(b"", s.read(2))
def test_start_unseekable(self):
with self.subTest(wrapper=TellableStream):
with self.assertRaises(OSError):
Substream(TellableStream(io.BytesIO(b"0123456789")), 3, 6)
with self.subTest(wrapper=UnseekableStream):
s = Substream(UnseekableStream(io.BytesIO(b"0123456789")), 3, 6)
self.assertEqual(3, s.start)
self.assertEqual(0, s.tell())