Long story short: Don’t change Python 2, and just restore the seek(-1) test in 3.

I agree in general it is better to skip a test than completely remove it. However, in Python 2, the test that Victor proposes to restore is redundant with test_file2k. Sys.stdin is always a Python-2-style file object, which for some reason or other can allow seek(-1).

Also, this bug was opened for Python 2, with the comment “works fine in 3.2”. I do not understand why the test was removed from Python 3.

For the Python 3 version of the test, the OSF/1 skip should not be necessary. Also, the truncate() test is probably redundant with the test_optional_abilities() method that I added in revision dc9e5f09ac0c (Issue 22854).