allmydata.test.cli.test_magic_folder.StatusMagicFolder.test_status fails on New Years Eve

[warner]

allmydata.test.cli.test_magic_folder.StatusMagicFolder.test_status just failed for me:

[FAIL]
Traceback (most recent call last):
  File "/home/warner/stuff/tahoe/tahoe/.tox/py27/local/lib/python2.7/site-packages/twisted/internet/defer.py", line 1386, in _inlineCallbacks
    result = g.send(result)
  File "/home/warner/stuff/tahoe/tahoe/src/allmydata/test/cli/test_magic_folder.py", line 336, in test_status
    stdout,
  File "/home/warner/stuff/tahoe/tahoe/.tox/py27/local/lib/python2.7/site-packages/twisted/trial/_synctest.py", line 492, in assertIn
    % (containee, container))
twisted.trial.unittest.FailTest: 'foo (1.23 kB): good, version=1, created 47 years ago' not in "Magic-folder status for 'default':\nLocal files:\n  foo (1.23 kB): good, version=1, created 48 years ago\n\nRemote files:\n"

allmydata.test.cli.test_magic_folder.StatusMagicFolder.test_status

To reproduce, set your system clock to about 9:20pm on 30-Dec-2017 in the CET timezone (central europe, UTC+1):

$ date
Sat Dec 30 21:24:43 CET 2017

I'm guessing this is a fencepost error in the way dates are being handled, and that it's more likely to fail near the end of the year.

[meejah]

Fixed via ​https://github.com/tahoe-lafs/tahoe-lafs/pull/453