$ python3.7
Python 3.7.4 (v3.7.4:e09359112e, Jul  8 2019, 14:54:52)
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> client.pymongo_test.test.insert_one({'_id': 1})
<pymongo.results.InsertOneResult object at 0x102bec5f0>
>>> ^D
$ python3.7 setup.py test -s test.test_custom_types
running test
running egg_info
writing pymongo.egg-info/PKG-INFO
writing dependency_links to pymongo.egg-info/dependency_links.txt
writing requirements to pymongo.egg-info/requires.txt
writing top-level names to pymongo.egg-info/top_level.txt
reading manifest file 'pymongo.egg-info/SOURCES.txt'
reading manifest template 'MANIFEST.in'
writing manifest file 'pymongo.egg-info/SOURCES.txt'
running build_ext
test_chaining_encoders_fails (test.test_custom_types.TestBSONCustomTypeEncoderAndFallbackEncoderTandem) ... ok
test_encode_custom_then_fallback (test.test_custom_types.TestBSONCustomTypeEncoderAndFallbackEncoderTandem) ... ok
test_encode_fallback_then_custom (test.test_custom_types.TestBSONCustomTypeEncoderAndFallbackEncoderTandem) ... ok
test_infinite_loop_exceeds_max_recursion_depth (test.test_custom_types.TestBSONCustomTypeEncoderAndFallbackEncoderTandem) ... ok
test_erroring_fallback_encoder (test.test_custom_types.TestBSONFallbackEncoder) ... ok
test_noop_fallback_encoder (test.test_custom_types.TestBSONFallbackEncoder) ... ok
test_simple (test.test_custom_types.TestBSONFallbackEncoder) ... ok
test_type_unencodable_by_fallback_encoder (test.test_custom_types.TestBSONFallbackEncoder) ... ok
test_instantiation (test.test_custom_types.TestBSONTypeEnDeCodecs) ... ok
test_type_checks (test.test_custom_types.TestBSONTypeEnDeCodecs) ... ok
test_break_resume_token (test.test_custom_types.TestClusterChangeStreamsWCustomTypes) ... ERROR
test_custom_type_in_pipeline (test.test_custom_types.TestClusterChangeStreamsWCustomTypes) ... ok
test_document_class (test.test_custom_types.TestClusterChangeStreamsWCustomTypes) ... ok
test_simple (test.test_custom_types.TestClusterChangeStreamsWCustomTypes) ... ok
test_break_resume_token (test.test_custom_types.TestCollectionChangeStreamsWCustomTypes) ... ok
test_custom_type_in_pipeline (test.test_custom_types.TestCollectionChangeStreamsWCustomTypes) ... ok
test_document_class (test.test_custom_types.TestCollectionChangeStreamsWCustomTypes) ... ok
test_simple (test.test_custom_types.TestCollectionChangeStreamsWCustomTypes) ... ok
test_aggregate_w_custom_type_decoder (test.test_custom_types.TestCollectionWCustomType) ... ok
test_command_errors_w_custom_type_decoder (test.test_custom_types.TestCollectionWCustomType) ... ok
test_distinct_w_custom_type (test.test_custom_types.TestCollectionWCustomType) ... ok
test_find_and_modify_w_custom_type_decoder (test.test_custom_types.TestCollectionWCustomType) ... ok
test_find_one_and__w_custom_type_decoder (test.test_custom_types.TestCollectionWCustomType) ... ok
test_find_w_custom_type_decoder (test.test_custom_types.TestCollectionWCustomType) ... ok
test_find_w_custom_type_decoder_and_document_class (test.test_custom_types.TestCollectionWCustomType) ... ok
test_group_w_custom_type (test.test_custom_types.TestCollectionWCustomType) ... skipped 'Server version must be at most 4.1.0.-1'
test_map_reduce_w_custom_type (test.test_custom_types.TestCollectionWCustomType) ... ok
test__bson_to_dict (test.test_custom_types.TestCustomPythonBSONTypeToBSONMonolithicCodec) ... ok
test__dict_to_bson (test.test_custom_types.TestCustomPythonBSONTypeToBSONMonolithicCodec) ... ok
test_decode_all (test.test_custom_types.TestCustomPythonBSONTypeToBSONMonolithicCodec) ... ok
test_decode_file_iter (test.test_custom_types.TestCustomPythonBSONTypeToBSONMonolithicCodec) ... ok
test_decode_iter (test.test_custom_types.TestCustomPythonBSONTypeToBSONMonolithicCodec) ... ok
test_encode_decode_roundtrip (test.test_custom_types.TestCustomPythonBSONTypeToBSONMonolithicCodec) ... ok
test__bson_to_dict (test.test_custom_types.TestCustomPythonBSONTypeToBSONMultiplexedCodec) ... ok
test__dict_to_bson (test.test_custom_types.TestCustomPythonBSONTypeToBSONMultiplexedCodec) ... ok
test_decode_all (test.test_custom_types.TestCustomPythonBSONTypeToBSONMultiplexedCodec) ... ok
test_decode_file_iter (test.test_custom_types.TestCustomPythonBSONTypeToBSONMultiplexedCodec) ... ok
test_decode_iter (test.test_custom_types.TestCustomPythonBSONTypeToBSONMultiplexedCodec) ... ok
test_encode_decode_roundtrip (test.test_custom_types.TestCustomPythonBSONTypeToBSONMultiplexedCodec) ... ok
test_break_resume_token (test.test_custom_types.TestDatabaseChangeStreamsWCustomTypes) ... ok
test_custom_type_in_pipeline (test.test_custom_types.TestDatabaseChangeStreamsWCustomTypes) ... ok
test_document_class (test.test_custom_types.TestDatabaseChangeStreamsWCustomTypes) ... ok
test_simple (test.test_custom_types.TestDatabaseChangeStreamsWCustomTypes) ... ok
test_grid_out_custom_opts (test.test_custom_types.TestGridFileCustomType) ... ok
test_builtin_types_override_fails (test.test_custom_types.TestTypeRegistry) ... ok
test_initialize_fail (test.test_custom_types.TestTypeRegistry) ... ok
test_simple (test.test_custom_types.TestTypeRegistry) ... ok
test_simple_separate_codecs (test.test_custom_types.TestTypeRegistry) ... ok
test_type_registry_eq (test.test_custom_types.TestTypeRegistry) ... ok
test_type_registry_repr (test.test_custom_types.TestTypeRegistry) ... ok

======================================================================
ERROR: test_break_resume_token (test.test_custom_types.TestClusterChangeStreamsWCustomTypes)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/shane/git/mongo-python-driver/test/test_custom_types.py", line 823, in test_break_resume_token
    self.insert_and_check(change_stream, docs[0], docs[0])
  File "/Users/shane/git/mongo-python-driver/test/test_custom_types.py", line 748, in insert_and_check
    self.input_target.insert_one(insert_doc)
  File "/Users/shane/git/mongo-python-driver/pymongo/collection.py", line 698, in insert_one
    session=session),
  File "/Users/shane/git/mongo-python-driver/pymongo/collection.py", line 612, in _insert
    bypass_doc_val, session)
  File "/Users/shane/git/mongo-python-driver/pymongo/collection.py", line 600, in _insert_one
    acknowledged, _insert_command, session)
  File "/Users/shane/git/mongo-python-driver/pymongo/mongo_client.py", line 1492, in _retryable_write
    return self._retry_with_session(retryable, func, s, None)
  File "/Users/shane/git/mongo-python-driver/pymongo/mongo_client.py", line 1385, in _retry_with_session
    return func(session, sock_info, retryable)
  File "/Users/shane/git/mongo-python-driver/pymongo/collection.py", line 597, in _insert_command
    _check_write_command_response(result)
  File "/Users/shane/git/mongo-python-driver/pymongo/helpers.py", line 221, in _check_write_command_response
    _raise_last_write_error(write_errors)
  File "/Users/shane/git/mongo-python-driver/pymongo/helpers.py", line 202, in _raise_last_write_error
    raise DuplicateKeyError(error.get("errmsg"), 11000, error)
pymongo.errors.DuplicateKeyError: E11000 duplicate key error collection: pymongo_test.test index: _id_ dup key: { _id: 1 }

----------------------------------------------------------------------
Ran 50 tests in 2.316s

FAILED (errors=1, skipped=1)