Tests for GCS

[william-silversmith]

Right now I'm sort of getting this tested by proxy via CloudVolume's tests. It's ugly though.

[fcollman]

there is a bug in the current implementation using the latest versions of crc32c cloud-volume and cloud-files.

metadata.py", line 71, in fetch_info
    info = self.cache.download_json(self.meta.join(self.mesh_path, 'info'))
  File "/usr/local/lib/python3.7/site-packages/cloudvolume/cacheservice.py", line 354, in download_json
    res = self.download( [ path ], compress=compress, progress=False )
  File "/usr/local/lib/python3.7/site-packages/cloudvolume/cacheservice.py", line 477, in download
    raise frag['error']
  File "/usr/local/lib/python3.7/site-packages/cloudfiles/cloudfiles.py", line 176, in download
    check_crc32c(path, content, server_hash)
  File "/usr/local/lib/python3.7/site-packages/cloudfiles/cloudfiles.py", line 153, in check_crc32c
    crc = crc32c(content)
  File "/usr/local/lib/python3.7/site-packages/cloudfiles/lib.py", line 155, in crc32c
    return crc32clib.value(binary) # an integer
AttributeError: module 'crc32c' has no attribute 'value'

[william-silversmith]

There was an issue with google-resumable-media and google-crc32c where their versions were conflicting with crc32c.

googleapis/google-resumable-media-python#162 (comment)

Can you double check to see if your version of google-crc32c is at 1.0.0?