'test_paginate_files': eventual consistency failure

[tseaver]

From https://travis-ci.org/GoogleCloudPlatform/gcloud-python/builds/155830290#L832-L838:

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FAIL: test_paginate_files (storage.TestStorageListFiles)
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Traceback (most recent call last):
  File "/home/travis/build/GoogleCloudPlatform/gcloud-python/system_tests/storage.py", line 248, in test_paginate_files
    self.assertTrue(iterator.next_page_token is not None)
AssertionError: False is not true

[dhermes]

@tseaver At the end of the day this is an eventual consistency error (surprising we've never seen it before). The values come from

response = self.bucket.list_blobs(max_results=2).get_next_page_response()

where we expect there to be 3 filenames:

FILENAMES = ('CloudLogo1', 'CloudLogo2', 'CloudLogo3')

So iterator.next_page_token is not None will be true if at the time the backend knew about all 3 files. But if not, then we see this failure.