Invalid on windows timezone test

[bpoldrack]

What is the problem?

In https://ci.appveyor.com/project/mih/datalad/build/1.0.20 the following test is failing, since time.tzset() is available on Unix only.

However, I don't quite get its purpose in the test in question:

def test_get_timestamp_suffix():
    # we need to patch temporarily TZ
    import time
    try:
        with patch.dict('os.environ', {'TZ': 'GMT'}):
            time.tzset()
            # skynet DOB
            assert_equal(get_timestamp_suffix(0), '-1970-01-01T00:00:00+0000')
            assert_equal(get_timestamp_suffix(0, prefix="+"),
                         '+1970-01-01T00:00:00+0000')
            # yoh found no way to mock things out and didn't want to provide
            # explicit call to anything to get current time with the timezone,
            # so disabling this test for now besides that it should return smth
            # sensible ;)
            #with patch.object(time, 'localtime', lambda: 1):
            #    assert_equal(get_timestamp_suffix(),
            #  '-1970-01-01T00:00:01+0000')  # skynet is 1 sec old
            assert(get_timestamp_suffix().startswith('-'))
    finally:
        time.tzset()

But timestamp 0 should always resolve to this very string. At the end of the day this is just calling time.gmtime(0), the result of which should be independent on local TZ, no? Do I miss something here, @yarikoptic ?
If I'm right, the use of time.tzset() is simply superfluous.