Update third_party/protobuf to protobuf-v3.0.0-beta-3

third_party/protobuf/src/google/protobuf/arena_nc_test.py

 #! /usr/bin/env python
 #
 # Protocol Buffers - Google's data interchange format
 # Copyright 2008 Google Inc.  All rights reserved.
 # https://developers.google.com/protocol-buffers/
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
@@ skipping 17 matching lines @@
 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 """Negative compilation unit tests for arena API."""
 
 import unittest
 
 from google3.testing.pybase import fake_target_util
-import unittest
+from google3.testing.pybase import unittest
 
 
 class ArenaNcTest(unittest.TestCase):
 
   def testCompilerErrors(self):
     """Runs a list of tests to verify compiler error messages."""
 
     # Defines a list of test specs, where each element is a tuple
     # (test name, list of regexes for matching the compiler errors).
     test_specs = [
         ('ARENA_PRIVATE_CONSTRUCTOR',
          [r'calling a protected constructor']),
         ('SANITY', None)]
 
     fake_target_util.AssertCcCompilerErrors(
         self,                         # The current test case.
         'google3/google/protobuf/arena_nc',  # The fake target file.
         'arena_nc.o',                 # The sub-target to build.
         test_specs                    # List of test specifications.
         )
 
 if __name__ == '__main__':
   unittest.main()