Fix flake8 and unit test run by adding missing pytest import and running black

Author: aseering

tests/unit/test_spanner.py

@@ -14,6 +14,9 @@
 
 
 import threading
+import unittest
+
+import pytest
 from google.protobuf.struct_pb2 import Struct
 from google.cloud.spanner_v1 import (
     PartialResultSet,
@@ -955,7 +958,9 @@ def test_transaction_should_use_transaction_id_returned_by_first_batch_update(se
             timeout=TIMEOUT,
         )
 
-    @pytest.mark.skip(reason="Inherently flaky, relies on thread crash swallowing in older Pytest")
+    @pytest.mark.skip(
+        reason="Inherently flaky, relies on thread crash swallowing in older Pytest"
+    )
     def test_transaction_for_concurrent_statement_should_begin_one_transaction_with_execute_update(
         self,
     ):
@@ -1029,7 +1034,9 @@ def test_transaction_for_concurrent_statement_should_begin_one_transaction_with_
         self.assertEqual(api.execute_sql.call_count, 2)
         self.assertEqual(api.execute_batch_dml.call_count, 1)
 
-    @pytest.mark.skip(reason="Inherently flaky, relies on thread crash swallowing in older Pytest")
+    @pytest.mark.skip(
+        reason="Inherently flaky, relies on thread crash swallowing in older Pytest"
+    )
     def test_transaction_for_concurrent_statement_should_begin_one_transaction_with_batch_update(
         self,
     ):
@@ -1096,7 +1103,9 @@ def test_transaction_for_concurrent_statement_should_begin_one_transaction_with_
         )
         self.assertEqual(actual_id_suffixes, expected_id_suffixes)
 
-    @pytest.mark.skip(reason="Inherently flaky, relies on thread crash swallowing in older Pytest")
+    @pytest.mark.skip(
+        reason="Inherently flaky, relies on thread crash swallowing in older Pytest"
+    )
     def test_transaction_for_concurrent_statement_should_begin_one_transaction_with_read(
         self,
     ):
@@ -1170,7 +1179,9 @@ def test_transaction_for_concurrent_statement_should_begin_one_transaction_with_
         )
         self.assertEqual(actual_id_suffixes, expected_id_suffixes)
 
-    @pytest.mark.skip(reason="Inherently flaky, relies on thread crash swallowing in older Pytest")
+    @pytest.mark.skip(
+        reason="Inherently flaky, relies on thread crash swallowing in older Pytest"
+    )
     def test_transaction_for_concurrent_statement_should_begin_one_transaction_with_query(
         self,
     ):