Merged revisions 77895-77896 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k

................
  r77895 | antoine.pitrou | 2010-01-31 23:47:27 +0100 (dim., 31 janv. 2010) | 12 lines

  Merged revisions 77890 via svnmerge from
  svn+ssh://pythondev@svn.python.org/python/trunk

  ........
    r77890 | antoine.pitrou | 2010-01-31 23:26:04 +0100 (dim., 31 janv. 2010) | 7 lines

    - Issue #6939: Fix file I/O objects in the `io` module to keep the original
      file position when calling `truncate()`.  It would previously change the
      file position to the given argument, which goes against the tradition of
      ftruncate() and other truncation APIs.  Patch by Pascal Chambon.
  ........
................
  r77896 | antoine.pitrou | 2010-02-01 00:12:29 +0100 (lun., 01 févr. 2010) | 3 lines

  r77895 broke doctest.
................
diff --git a/Lib/test/test_fileio.py b/Lib/test/test_fileio.py
index 7a9b780..f89c542 100644
--- a/Lib/test/test_fileio.py
+++ b/Lib/test/test_fileio.py
@@ -330,6 +330,17 @@
             f.close()
             self.fail("no error for invalid mode: %s" % bad_mode)
 
+    def testTruncate(self):
+        f = _FileIO(TESTFN, 'w')
+        f.write(bytes(bytearray(range(10))))
+        self.assertEqual(f.tell(), 10)
+        f.truncate(5)
+        self.assertEqual(f.tell(), 10)
+        self.assertEqual(f.seek(0, os.SEEK_END), 5)
+        f.truncate(15)
+        self.assertEqual(f.tell(), 5)
+        self.assertEqual(f.seek(0, os.SEEK_END), 15)
+
     def testTruncateOnWindows(self):
         def bug801631():
             # SF bug <http://www.python.org/sf/801631>