Issue #5506: BytesIO objects now have a getbuffer() method exporting a
view of their contents without duplicating them. The view is both readable
and writable.
diff --git a/Lib/test/test_memoryio.py b/Lib/test/test_memoryio.py
index 0decda5..dcf6d51 100644
--- a/Lib/test/test_memoryio.py
+++ b/Lib/test/test_memoryio.py
@@ -384,7 +384,31 @@
del __main__.PickleTestMemIO
-class PyBytesIOTest(MemoryTestMixin, MemorySeekTestMixin, unittest.TestCase):
+class BytesIOMixin:
+
+ 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")
+ # Trying to change the size of the BytesIO while a buffer is exported
+ # raises a BufferError.
+ self.assertRaises(BufferError, memio.write, b'x' * 100)
+ self.assertRaises(BufferError, memio.truncate)
+ # Mutating the buffer updates the BytesIO
+ buf[3:6] = b"abc"
+ self.assertEqual(bytes(buf), b"123abc7890")
+ self.assertEqual(memio.getvalue(), b"123abc7890")
+ # After the buffer gets released, we can resize the BytesIO again
+ del buf
+ support.gc_collect()
+ memio.truncate()
+
+
+class PyBytesIOTest(MemoryTestMixin, MemorySeekTestMixin,
+ BytesIOMixin, unittest.TestCase):
UnsupportedOperation = pyio.UnsupportedOperation