Mutable update tests are sensitive to the number of servers

[markberger]

When the number of servers used in allmydata.test.test_mutable.Update is changed from the default value to ten to something greater than ten, almost all of the tests fail due to key error.

===============================================================================
[FAIL]
Traceback (most recent call last):
  File "/Users/markberger/Code/tahoe-lafs/src/allmydata/test/test_mutable.py", line 3663, in <lambda>
    self.failUnlessEqual(results, new_data))
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/twisted/trial/_synctest.py", line 356, in assertEqual
    % (msg, pformat(first), pformat(second)))
twisted.trial.unittest.FailTest: not equal:
a = 'test datatest datatest datatest datatest datatest datatest datatest datatest datatest data'
b = 'test datatest datatest datatest datatest datatest datatest datatest datatest datatest dataappended'


allmydata.test.test_mutable.Update.test_update_sdmf
===============================================================================
[ERROR]
Traceback (most recent call last):
Failure: allmydata.mutable.common.NotEnoughServersError: ("Publish ran out of good servers, last failure was: [Failure instance: Traceback: <type 'exceptions.KeyError'>: 0\n/Users/markberger/Code/tahoe-lafs/src/allmydata/mutable/publish.py:642:_push\n/Users/markberger/Code/tahoe-lafs/src/allmydata/mutable/publish.py:662:push_segment\n/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/twisted/internet/defer.py:304:addCallback\n/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/twisted/internet/defer.py:293:addCallbacks\n--- <exception caught here> ---\n/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/twisted/internet/defer.py:575:_runCallbacks\n/Users/markberger/Code/tahoe-lafs/src/allmydata/mutable/publish.py:767:_push_segment\n]", None)

allmydata.test.test_mutable.Update.test_append
allmydata.test.test_mutable.Update.test_append_power_of_two
allmydata.test.test_mutable.Update.test_multiple_segment_replace
allmydata.test.test_mutable.Update.test_replace_beginning
allmydata.test.test_mutable.Update.test_replace_segstart1
===============================================================================
[ERROR]
Traceback (most recent call last):
Failure: allmydata.mutable.common.NotEnoughServersError: ("Publish ran out of good servers, last failure was: [Failure instance: Traceback: <type 'exceptions.KeyError'>: 1\n/Users/markberger/Code/tahoe-lafs/src/allmydata/mutable/publish.py:642:_push\n/Users/markberger/Code/tahoe-lafs/src/allmydata/mutable/publish.py:662:push_segment\n/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/twisted/internet/defer.py:304:addCallback\n/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/twisted/internet/defer.py:293:addCallbacks\n--- <exception caught here> ---\n/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/twisted/internet/defer.py:575:_runCallbacks\n/Users/markberger/Code/tahoe-lafs/src/allmydata/mutable/publish.py:767:_push_segment\n]", None)

allmydata.test.test_mutable.Update.test_replace_and_extend
allmydata.test.test_mutable.Update.test_replace_in_last_segment
allmydata.test.test_mutable.Update.test_replace_locations
allmydata.test.test_mutable.Update.test_replace_middle
allmydata.test.test_mutable.Update.test_replace_zero_length_middle
===============================================================================
[ERROR]
Traceback (most recent call last):
  File "/Users/markberger/Code/tahoe-lafs/src/allmydata/mutable/filenode.py", line 1177, in _build_uploadable_and_finish
    return p.update(u, offset, segments_and_bht[2], self._version)
  File "/Users/markberger/Code/tahoe-lafs/src/allmydata/mutable/publish.py", line 341, in update
    self._push()
  File "/Users/markberger/Code/tahoe-lafs/src/allmydata/mutable/publish.py", line 642, in _push
    return self.push_segment(self._current_segment)
  File "/Users/markberger/Code/tahoe-lafs/src/allmydata/mutable/publish.py", line 659, in push_segment
    return self._push()
  File "/Users/markberger/Code/tahoe-lafs/src/allmydata/mutable/publish.py", line 645, in _push
    return self.push_everything_else()
  File "/Users/markberger/Code/tahoe-lafs/src/allmydata/mutable/publish.py", line 778, in push_everything_else
    self.push_blockhashes()
  File "/Users/markberger/Code/tahoe-lafs/src/allmydata/mutable/publish.py", line 806, in push_blockhashes
    writers = self.writers[shnum]
exceptions.KeyError: 0

allmydata.test.test_mutable.Update.test_replace_zero_length_beginning
allmydata.test.test_mutable.Update.test_replace_zero_length_segstart1
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Ran 14 tests in 58.570s