Make a few more tests pass with the new I/O library.

Fix the truncate() semantics -- it should not affect the current position.
Switch wave.py/chunk.py to struct.unpack_from() to support bytes.
Don't use writelines() on binary files (test_fileinput.py).

1 files changed, 0 insertions, 2 deletions

diff --git a/Lib/io.py b/Lib/io.py
index 4465e9e..8b5c958 100644
--- a/Lib/io.py
+++ b/Lib/io.py
@@ -551,8 +551,6 @@ class _MemoryIOMixin(BufferedIOBase):
     def truncate(self, pos=None):
         if pos is None:
             pos = self._pos
-        else:
-            self._pos = max(0, pos)
         del self._buffer[pos:]
         return pos