test: add system test SQL to run tests locally (#74)

* test: add system test SQL to run tests locally

I was missing the `public_samples_copy` dataset when trying to run the
system tests locally.

Also, it is unnecessary to use the `mock` backfill package now that
Python 3.6+ is required.

* revert change to use mock built-in

needs AsyncMock backfill

tests/system/assets/public_samples_copy.sql

@@ -0,0 +1,17 @@
+-- Copyright 2020 Google LLC
+--
+-- 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
+--
+--     https://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.
+
+CREATE TABLE public_samples_copy.shakespeare
+AS
+SELECT * FROM `bigquery-public-data.samples.shakespeare`

tests/unit/test_client_v1.py

@@ -12,8 +12,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from unittest import mock
+
 from google.api_core.gapic_v1 import client_info
-import mock
 import pytest
 
 from google.cloud.bigquery_storage import types

tests/unit/test_reader_v1.py

@@ -18,10 +18,10 @@
 import decimal
 import itertools
 import json
+from unittest import mock
 
 import fastavro
 import pyarrow
-import mock
 import pandas
 import pandas.testing
 import pytest