test_transaction.py

# Copyright 2016 Google LLC All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


import mock

from google.cloud.spanner_v1 import RequestOptions
from google.cloud.spanner_v1 import Type
from google.cloud.spanner_v1 import TypeCode
from google.api_core.retry import Retry
from google.api_core import gapic_v1

from tests._helpers import OpenTelemetryBase, StatusCode

TABLE_NAME = "citizens"
COLUMNS = ["email", "first_name", "last_name", "age"]
VALUES = [
    ["phred@exammple.com", "Phred", "Phlyntstone", 32],
    ["bharney@example.com", "Bharney", "Rhubble", 31],
]
DML_QUERY = """\
INSERT INTO citizens(first_name, last_name, age)
VALUES ("Phred", "Phlyntstone", 32)
"""
DML_QUERY_WITH_PARAM = """
INSERT INTO citizens(first_name, last_name, age)
VALUES ("Phred", "Phlyntstone", @age)
"""
PARAMS = {"age": 30}
PARAM_TYPES = {"age": Type(code=TypeCode.INT64)}


class TestTransaction(OpenTelemetryBase):

    PROJECT_ID = "project-id"
    INSTANCE_ID = "instance-id"
    INSTANCE_NAME = "projects/" + PROJECT_ID + "/instances/" + INSTANCE_ID
    DATABASE_ID = "database-id"
    DATABASE_NAME = INSTANCE_NAME + "/databases/" + DATABASE_ID
    SESSION_ID = "session-id"
    SESSION_NAME = DATABASE_NAME + "/sessions/" + SESSION_ID
    TRANSACTION_ID = b"DEADBEEF"

    BASE_ATTRIBUTES = {
        "db.type": "spanner",
        "db.url": "spanner.googleapis.com",
        "db.instance": "testing",
        "net.host.name": "spanner.googleapis.com",
    }

    def _getTargetClass(self):
        from google.cloud.spanner_v1.transaction import Transaction

        return Transaction

    def _make_one(self, session, *args, **kwargs):
        transaction = self._getTargetClass()(session, *args, **kwargs)
        session._transaction = transaction
        return transaction

    def _make_spanner_api(self):
        from google.cloud.spanner_v1 import SpannerClient

        return mock.create_autospec(SpannerClient, instance=True)

    def test_ctor_session_w_existing_txn(self):
        session = _Session()
        session._transaction = object()
        with self.assertRaises(ValueError):
            self._make_one(session)

    def test_ctor_defaults(self):
        session = _Session()
        transaction = self._make_one(session)
        self.assertIs(transaction._session, session)
        self.assertIsNone(transaction._transaction_id)
        self.assertIsNone(transaction.committed)
        self.assertFalse(transaction.rolled_back)
        self.assertTrue(transaction._multi_use)
        self.assertEqual(transaction._execute_sql_count, 0)

    def test__check_state_not_begun(self):
        session = _Session()
        transaction = self._make_one(session)
        with self.assertRaises(ValueError):
            transaction._check_state()

    def test__check_state_already_committed(self):
        session = _Session()
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID
        transaction.committed = object()
        with self.assertRaises(ValueError):
            transaction._check_state()

    def test__check_state_already_rolled_back(self):
        session = _Session()
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID
        transaction.rolled_back = True
        with self.assertRaises(ValueError):
            transaction._check_state()

    def test__check_state_ok(self):
        session = _Session()
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID
        transaction._check_state()  # does not raise

    def test__make_txn_selector(self):
        session = _Session()
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID
        selector = transaction._make_txn_selector()
        self.assertEqual(selector.id, self.TRANSACTION_ID)

    def test_begin_already_begun(self):
        session = _Session()
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID
        with self.assertRaises(ValueError):
            transaction.begin()

        self.assertNoSpans()

    def test_begin_already_rolled_back(self):
        session = _Session()
        transaction = self._make_one(session)
        transaction.rolled_back = True
        with self.assertRaises(ValueError):
            transaction.begin()

        self.assertNoSpans()

    def test_begin_already_committed(self):
        session = _Session()
        transaction = self._make_one(session)
        transaction.committed = object()
        with self.assertRaises(ValueError):
            transaction.begin()

        self.assertNoSpans()

    def test_begin_w_other_error(self):
        database = _Database()
        database.spanner_api = self._make_spanner_api()
        database.spanner_api.begin_transaction.side_effect = RuntimeError()
        session = _Session(database)
        transaction = self._make_one(session)

        with self.assertRaises(RuntimeError):
            transaction.begin()

        self.assertSpanAttributes(
            "CloudSpanner.BeginTransaction",
            status=StatusCode.ERROR,
            attributes=TestTransaction.BASE_ATTRIBUTES,
        )

    def test_begin_ok(self):
        from google.cloud.spanner_v1 import Transaction as TransactionPB

        transaction_pb = TransactionPB(id=self.TRANSACTION_ID)
        database = _Database()
        api = database.spanner_api = _FauxSpannerAPI(
            _begin_transaction_response=transaction_pb
        )
        session = _Session(database)
        transaction = self._make_one(session)

        txn_id = transaction.begin()

        self.assertEqual(txn_id, self.TRANSACTION_ID)
        self.assertEqual(transaction._transaction_id, self.TRANSACTION_ID)

        session_id, txn_options, metadata = api._begun
        self.assertEqual(session_id, session.name)
        self.assertTrue(type(txn_options).pb(txn_options).HasField("read_write"))
        self.assertEqual(metadata, [("google-cloud-resource-prefix", database.name)])

        self.assertSpanAttributes(
            "CloudSpanner.BeginTransaction", attributes=TestTransaction.BASE_ATTRIBUTES
        )

    def test_begin_read_only(self):
        from google.cloud.spanner_v1 import Transaction as TransactionPB

        transaction_pb = TransactionPB(id=self.TRANSACTION_ID)
        database = _Database()
        api = database.spanner_api = _FauxSpannerAPI(
            _begin_transaction_response=transaction_pb
        )
        session = _Session(database)
        transaction = self._make_one(session)

        txn_id = transaction.begin(read_only=True)

        self.assertEqual(txn_id, self.TRANSACTION_ID)
        self.assertEqual(transaction._transaction_id, self.TRANSACTION_ID)

        session_id, txn_options, metadata = api._begun
        self.assertEqual(session_id, session.name)
        self.assertTrue(type(txn_options).pb(txn_options).HasField("read_only"))
        self.assertEqual(metadata, [("google-cloud-resource-prefix", database.name)])

        self.assertSpanAttributes(
            "CloudSpanner.BeginTransaction", attributes=TestTransaction.BASE_ATTRIBUTES
        )

    def test_rollback_not_begun(self):
        session = _Session()
        transaction = self._make_one(session)
        with self.assertRaises(ValueError):
            transaction.rollback()

        self.assertNoSpans()

    def test_rollback_already_committed(self):
        session = _Session()
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID
        transaction.committed = object()
        with self.assertRaises(ValueError):
            transaction.rollback()

        self.assertNoSpans()

    def test_rollback_already_rolled_back(self):
        session = _Session()
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID
        transaction.rolled_back = True
        with self.assertRaises(ValueError):
            transaction.rollback()

        self.assertNoSpans()

    def test_rollback_w_other_error(self):
        database = _Database()
        database.spanner_api = self._make_spanner_api()
        database.spanner_api.rollback.side_effect = RuntimeError("other error")
        session = _Session(database)
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID
        transaction.insert(TABLE_NAME, COLUMNS, VALUES)

        with self.assertRaises(RuntimeError):
            transaction.rollback()

        self.assertFalse(transaction.rolled_back)

        self.assertSpanAttributes(
            "CloudSpanner.Rollback",
            status=StatusCode.ERROR,
            attributes=TestTransaction.BASE_ATTRIBUTES,
        )

    def test_rollback_ok(self):
        from google.protobuf.empty_pb2 import Empty

        empty_pb = Empty()
        database = _Database()
        api = database.spanner_api = _FauxSpannerAPI(_rollback_response=empty_pb)
        session = _Session(database)
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID
        transaction.replace(TABLE_NAME, COLUMNS, VALUES)

        transaction.rollback()

        self.assertTrue(transaction.rolled_back)
        self.assertIsNone(session._transaction)

        session_id, txn_id, metadata = api._rolled_back
        self.assertEqual(session_id, session.name)
        self.assertEqual(txn_id, self.TRANSACTION_ID)
        self.assertEqual(metadata, [("google-cloud-resource-prefix", database.name)])

        self.assertSpanAttributes(
            "CloudSpanner.Rollback", attributes=TestTransaction.BASE_ATTRIBUTES
        )

    def test_commit_not_begun(self):
        session = _Session()
        transaction = self._make_one(session)
        with self.assertRaises(ValueError):
            transaction.commit()

        self.assertNoSpans()

    def test_commit_already_committed(self):
        session = _Session()
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID
        transaction.committed = object()
        with self.assertRaises(ValueError):
            transaction.commit()

        self.assertNoSpans()

    def test_commit_already_rolled_back(self):
        session = _Session()
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID
        transaction.rolled_back = True
        with self.assertRaises(ValueError):
            transaction.commit()

        self.assertNoSpans()

    def test_commit_w_other_error(self):
        database = _Database()
        database.spanner_api = self._make_spanner_api()
        database.spanner_api.commit.side_effect = RuntimeError()
        session = _Session(database)
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID
        transaction.replace(TABLE_NAME, COLUMNS, VALUES)

        with self.assertRaises(RuntimeError):
            transaction.commit()

        self.assertIsNone(transaction.committed)

        self.assertSpanAttributes(
            "CloudSpanner.Commit",
            status=StatusCode.ERROR,
            attributes=dict(TestTransaction.BASE_ATTRIBUTES, num_mutations=1),
        )

    def _commit_helper(self, mutate=True, return_commit_stats=False):
        import datetime
        from google.cloud.spanner_v1 import CommitResponse
        from google.cloud.spanner_v1.keyset import KeySet
        from google.cloud._helpers import UTC

        now = datetime.datetime.utcnow().replace(tzinfo=UTC)
        keys = [[0], [1], [2]]
        keyset = KeySet(keys=keys)
        response = CommitResponse(commit_timestamp=now)
        if return_commit_stats:
            response.commit_stats.mutation_count = 4
        database = _Database()
        api = database.spanner_api = _FauxSpannerAPI(_commit_response=response)
        session = _Session(database)
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID

        if mutate:
            transaction.delete(TABLE_NAME, keyset)

        transaction.commit(return_commit_stats=return_commit_stats)

        self.assertEqual(transaction.committed, now)
        self.assertIsNone(session._transaction)

        session_id, mutations, txn_id, metadata = api._committed
        self.assertEqual(session_id, session.name)
        self.assertEqual(txn_id, self.TRANSACTION_ID)
        self.assertEqual(mutations, transaction._mutations)
        self.assertEqual(metadata, [("google-cloud-resource-prefix", database.name)])

        if return_commit_stats:
            self.assertEqual(transaction.commit_stats.mutation_count, 4)

        self.assertSpanAttributes(
            "CloudSpanner.Commit",
            attributes=dict(
                TestTransaction.BASE_ATTRIBUTES,
                num_mutations=len(transaction._mutations),
            ),
        )

    def test_commit_no_mutations(self):
        self._commit_helper(mutate=False)

    def test_commit_w_mutations(self):
        self._commit_helper(mutate=True)

    def test_commit_w_return_commit_stats(self):
        self._commit_helper(return_commit_stats=True)

    def test__make_params_pb_w_params_wo_param_types(self):
        session = _Session()
        transaction = self._make_one(session)

        with self.assertRaises(ValueError):
            transaction._make_params_pb(PARAMS, None)

    def test__make_params_pb_wo_params_w_param_types(self):
        session = _Session()
        transaction = self._make_one(session)

        with self.assertRaises(ValueError):
            transaction._make_params_pb(None, PARAM_TYPES)

    def test__make_params_pb_w_params_w_param_types(self):
        from google.protobuf.struct_pb2 import Struct
        from google.cloud.spanner_v1._helpers import _make_value_pb

        session = _Session()
        transaction = self._make_one(session)

        params_pb = transaction._make_params_pb(PARAMS, PARAM_TYPES)

        expected_params = Struct(
            fields={key: _make_value_pb(value) for (key, value) in PARAMS.items()}
        )
        self.assertEqual(params_pb, expected_params)

    def test_execute_update_other_error(self):
        database = _Database()
        database.spanner_api = self._make_spanner_api()
        database.spanner_api.execute_sql.side_effect = RuntimeError()
        session = _Session(database)
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID

        with self.assertRaises(RuntimeError):
            transaction.execute_update(DML_QUERY)

    def test_execute_update_w_params_wo_param_types(self):
        database = _Database()
        database.spanner_api = self._make_spanner_api()
        session = _Session(database)
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID

        with self.assertRaises(ValueError):
            transaction.execute_update(DML_QUERY_WITH_PARAM, PARAMS)

    def _execute_update_helper(
        self,
        count=0,
        query_options=None,
        request_options=None,
        retry=gapic_v1.method.DEFAULT,
        timeout=gapic_v1.method.DEFAULT,
    ):
        from google.protobuf.struct_pb2 import Struct
        from google.cloud.spanner_v1 import (
            ResultSet,
            ResultSetStats,
        )
        from google.cloud.spanner_v1 import TransactionSelector
        from google.cloud.spanner_v1._helpers import (
            _make_value_pb,
            _merge_query_options,
        )
        from google.cloud.spanner_v1 import ExecuteSqlRequest

        MODE = 2  # PROFILE
        stats_pb = ResultSetStats(row_count_exact=1)
        database = _Database()
        api = database.spanner_api = self._make_spanner_api()
        api.execute_sql.return_value = ResultSet(stats=stats_pb)
        session = _Session(database)
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID
        transaction._execute_sql_count = count

        row_count = transaction.execute_update(
            DML_QUERY_WITH_PARAM,
            PARAMS,
            PARAM_TYPES,
            query_mode=MODE,
            query_options=query_options,
            request_options=request_options,
            retry=retry,
            timeout=timeout,
        )

        self.assertEqual(row_count, 1)

        expected_transaction = TransactionSelector(id=self.TRANSACTION_ID)
        expected_params = Struct(
            fields={key: _make_value_pb(value) for (key, value) in PARAMS.items()}
        )

        expected_query_options = database._instance._client._query_options
        if query_options:
            expected_query_options = _merge_query_options(
                expected_query_options, query_options
            )

        expected_request = ExecuteSqlRequest(
            session=self.SESSION_NAME,
            sql=DML_QUERY_WITH_PARAM,
            transaction=expected_transaction,
            params=expected_params,
            param_types=PARAM_TYPES,
            query_mode=MODE,
            query_options=expected_query_options,
            request_options=request_options,
            seqno=count,
        )
        api.execute_sql.assert_called_once_with(
            request=expected_request,
            retry=retry,
            timeout=timeout,
            metadata=[("google-cloud-resource-prefix", database.name)],
        )

        self.assertEqual(transaction._execute_sql_count, count + 1)

    def test_execute_update_new_transaction(self):
        self._execute_update_helper()

    def test_execute_update_w_count(self):
        self._execute_update_helper(count=1)

    def test_execute_update_w_timeout_param(self):
        self._execute_update_helper(timeout=2.0)

    def test_execute_update_w_retry_param(self):
        self._execute_update_helper(retry=Retry(deadline=60))

    def test_execute_update_w_timeout_and_retry_params(self):
        self._execute_update_helper(retry=Retry(deadline=60), timeout=2.0)

    def test_execute_update_error(self):
        database = _Database()
        database.spanner_api = self._make_spanner_api()
        database.spanner_api.execute_sql.side_effect = RuntimeError()
        session = _Session(database)
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID

        with self.assertRaises(RuntimeError):
            transaction.execute_update(DML_QUERY)

        self.assertEqual(transaction._execute_sql_count, 1)

    def test_execute_update_w_query_options(self):
        from google.cloud.spanner_v1 import ExecuteSqlRequest

        self._execute_update_helper(
            query_options=ExecuteSqlRequest.QueryOptions(optimizer_version="3")
        )

    def test_execute_update_w_request_options(self):
        self._execute_update_helper(
            request_options=RequestOptions(
                priority=RequestOptions.Priority.PRIORITY_MEDIUM
            )
        )

    def test_batch_update_other_error(self):
        database = _Database()
        database.spanner_api = self._make_spanner_api()
        database.spanner_api.execute_batch_dml.side_effect = RuntimeError()
        session = _Session(database)
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID

        with self.assertRaises(RuntimeError):
            transaction.batch_update(statements=[DML_QUERY])

    def _batch_update_helper(self, error_after=None, count=0, request_options=None):
        from google.rpc.status_pb2 import Status
        from google.protobuf.struct_pb2 import Struct
        from google.cloud.spanner_v1 import param_types
        from google.cloud.spanner_v1 import ResultSet
        from google.cloud.spanner_v1 import ResultSetStats
        from google.cloud.spanner_v1 import ExecuteBatchDmlRequest
        from google.cloud.spanner_v1 import ExecuteBatchDmlResponse
        from google.cloud.spanner_v1 import TransactionSelector
        from google.cloud.spanner_v1._helpers import _make_value_pb

        insert_dml = "INSERT INTO table(pkey, desc) VALUES (%pkey, %desc)"
        insert_params = {"pkey": 12345, "desc": "DESCRIPTION"}
        insert_param_types = {"pkey": param_types.INT64, "desc": param_types.STRING}
        update_dml = 'UPDATE table SET desc = desc + "-amended"'
        delete_dml = "DELETE FROM table WHERE desc IS NULL"

        dml_statements = [
            (insert_dml, insert_params, insert_param_types),
            update_dml,
            delete_dml,
        ]

        stats_pbs = [
            ResultSetStats(row_count_exact=1),
            ResultSetStats(row_count_exact=2),
            ResultSetStats(row_count_exact=3),
        ]
        if error_after is not None:
            stats_pbs = stats_pbs[:error_after]
            expected_status = Status(code=400)
        else:
            expected_status = Status(code=200)
        expected_row_counts = [stats.row_count_exact for stats in stats_pbs]

        response = ExecuteBatchDmlResponse(
            status=expected_status,
            result_sets=[ResultSet(stats=stats_pb) for stats_pb in stats_pbs],
        )
        database = _Database()
        api = database.spanner_api = self._make_spanner_api()
        api.execute_batch_dml.return_value = response
        session = _Session(database)
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID
        transaction._execute_sql_count = count

        status, row_counts = transaction.batch_update(
            dml_statements, request_options=request_options
        )

        self.assertEqual(status, expected_status)
        self.assertEqual(row_counts, expected_row_counts)

        expected_transaction = TransactionSelector(id=self.TRANSACTION_ID)
        expected_insert_params = Struct(
            fields={
                key: _make_value_pb(value) for (key, value) in insert_params.items()
            }
        )
        expected_statements = [
            ExecuteBatchDmlRequest.Statement(
                sql=insert_dml,
                params=expected_insert_params,
                param_types=insert_param_types,
            ),
            ExecuteBatchDmlRequest.Statement(sql=update_dml),
            ExecuteBatchDmlRequest.Statement(sql=delete_dml),
        ]

        expected_request = ExecuteBatchDmlRequest(
            session=self.SESSION_NAME,
            transaction=expected_transaction,
            statements=expected_statements,
            seqno=count,
            request_options=request_options,
        )
        api.execute_batch_dml.assert_called_once_with(
            request=expected_request,
            metadata=[("google-cloud-resource-prefix", database.name)],
        )

        self.assertEqual(transaction._execute_sql_count, count + 1)

    def test_batch_update_wo_errors(self):
        self._batch_update_helper(
            request_options=RequestOptions(
                priority=RequestOptions.Priority.PRIORITY_MEDIUM
            ),
        )

    def test_batch_update_w_errors(self):
        self._batch_update_helper(error_after=2, count=1)

    def test_batch_update_error(self):
        from google.cloud.spanner_v1 import Type
        from google.cloud.spanner_v1 import TypeCode

        database = _Database()
        api = database.spanner_api = self._make_spanner_api()
        api.execute_batch_dml.side_effect = RuntimeError()
        session = _Session(database)
        transaction = self._make_one(session)
        transaction._transaction_id = self.TRANSACTION_ID

        insert_dml = "INSERT INTO table(pkey, desc) VALUES (%pkey, %desc)"
        insert_params = {"pkey": 12345, "desc": "DESCRIPTION"}
        insert_param_types = {
            "pkey": Type(code=TypeCode.INT64),
            "desc": Type(code=TypeCode.STRING),
        }
        update_dml = 'UPDATE table SET desc = desc + "-amended"'
        delete_dml = "DELETE FROM table WHERE desc IS NULL"

        dml_statements = [
            (insert_dml, insert_params, insert_param_types),
            update_dml,
            delete_dml,
        ]

        with self.assertRaises(RuntimeError):
            transaction.batch_update(dml_statements)

        self.assertEqual(transaction._execute_sql_count, 1)

    def test_context_mgr_success(self):
        import datetime
        from google.cloud.spanner_v1 import CommitResponse
        from google.cloud.spanner_v1 import Transaction as TransactionPB
        from google.cloud._helpers import UTC

        transaction_pb = TransactionPB(id=self.TRANSACTION_ID)
        now = datetime.datetime.utcnow().replace(tzinfo=UTC)
        response = CommitResponse(commit_timestamp=now)
        database = _Database()
        api = database.spanner_api = _FauxSpannerAPI(
            _begin_transaction_response=transaction_pb, _commit_response=response
        )
        session = _Session(database)
        transaction = self._make_one(session)

        with transaction:
            transaction.insert(TABLE_NAME, COLUMNS, VALUES)

        self.assertEqual(transaction.committed, now)

        session_id, mutations, txn_id, metadata = api._committed
        self.assertEqual(session_id, self.SESSION_NAME)
        self.assertEqual(txn_id, self.TRANSACTION_ID)
        self.assertEqual(mutations, transaction._mutations)
        self.assertEqual(metadata, [("google-cloud-resource-prefix", database.name)])

    def test_context_mgr_failure(self):
        from google.protobuf.empty_pb2 import Empty

        empty_pb = Empty()
        from google.cloud.spanner_v1 import Transaction as TransactionPB

        transaction_pb = TransactionPB(id=self.TRANSACTION_ID)
        database = _Database()
        api = database.spanner_api = _FauxSpannerAPI(
            _begin_transaction_response=transaction_pb, _rollback_response=empty_pb
        )
        session = _Session(database)
        transaction = self._make_one(session)

        with self.assertRaises(Exception):
            with transaction:
                transaction.insert(TABLE_NAME, COLUMNS, VALUES)
                raise Exception("bail out")

        self.assertEqual(transaction.committed, None)
        self.assertTrue(transaction.rolled_back)
        self.assertEqual(len(transaction._mutations), 1)

        self.assertEqual(api._committed, None)

        session_id, txn_id, metadata = api._rolled_back
        self.assertEqual(session_id, session.name)
        self.assertEqual(txn_id, self.TRANSACTION_ID)
        self.assertEqual(metadata, [("google-cloud-resource-prefix", database.name)])


class _Client(object):
    def __init__(self):
        from google.cloud.spanner_v1 import ExecuteSqlRequest

        self._query_options = ExecuteSqlRequest.QueryOptions(optimizer_version="1")


class _Instance(object):
    def __init__(self):
        self._client = _Client()


class _Database(object):
    def __init__(self):
        self.name = "testing"
        self._instance = _Instance()


class _Session(object):

    _transaction = None

    def __init__(self, database=None, name=TestTransaction.SESSION_NAME):
        self._database = database
        self.name = name


class _FauxSpannerAPI(object):

    _committed = None

    def __init__(self, **kwargs):
        self.__dict__.update(**kwargs)

    def begin_transaction(self, session=None, options=None, metadata=None):
        self._begun = (session, options, metadata)
        return self._begin_transaction_response

    def rollback(self, session=None, transaction_id=None, metadata=None):
        self._rolled_back = (session, transaction_id, metadata)
        return self._rollback_response

    def commit(
        self, request=None, metadata=None,
    ):
        assert not request.single_use_transaction
        self._committed = (
            request.session,
            request.mutations,
            request.transaction_id,
            metadata,
        )
        return self._commit_response