Return just row count from 'Transaction.execute_update'.

Also, drop the 'partition' argument to it:  not appropriate to the
usecase.

spanner/google/cloud/spanner_v1/transaction.py

@@ -129,7 +129,7 @@ def commit(self):
         return self.committed
 
     def execute_update(self, dml, params=None, param_types=None,
-                       query_mode=None, partition=None):
+                       query_mode=None):
         """Perform an ``ExecuteSql`` API request with DML.
 
         :type dml: str
@@ -149,10 +149,6 @@ def execute_update(self, dml, params=None, param_types=None,
         :param query_mode: Mode governing return of results / query plan. See
             https://cloud.google.com/spanner/reference/rpc/google.spanner.v1#google.spanner.v1.ExecuteSqlRequest.QueryMode1
 
-        :type partition: bytes
-        :param partition: (Optional) one of the partition tokens returned
-                          from :meth:`partition_query`.
-
         :rtype:
             :class:`google.cloud.spanner_v1.proto.ExecuteSqlRequest.ResultSetStats`
         :returns:
@@ -180,13 +176,12 @@ def execute_update(self, dml, params=None, param_types=None,
             params=params_pb,
             param_types=param_types,
             query_mode=query_mode,
-            partition_token=partition,
             seqno=self._execute_sql_count,
             metadata=metadata,
         )
 
         self._execute_sql_count += 1
-        return response.stats
+        return response.stats.row_count_exact
 
     def __enter__(self):
         """Begin ``with`` block."""

spanner/tests/system/test_system.py

@@ -692,8 +692,8 @@ def test_transaction_execute_update_read_commit(self):
             self.assertEqual(rows, [])
 
             for insert_statement in self._generate_insert_statements():
-                result = transaction.execute_update(insert_statement)
-                self.assertEqual(result.row_count_exact, 1)
+                row_count = transaction.execute_update(insert_statement)
+                self.assertEqual(row_count, 1)
 
             # Rows inserted via DML *can* be read before commit.
             during_rows = list(
@@ -722,8 +722,8 @@ def test_transaction_execute_update_then_insert_commit(self):
             rows = list(transaction.read(self.TABLE, self.COLUMNS, self.ALL))
             self.assertEqual(rows, [])
 
-            result = transaction.execute_update(insert_statement)
-            self.assertEqual(result.row_count_exact, 1)
+            row_count = transaction.execute_update(insert_statement)
+            self.assertEqual(row_count, 1)
 
             transaction.insert(self.TABLE, self.COLUMNS, self.ROW_DATA[1:])
 

spanner/tests/unit/test_transaction.py

@@ -325,7 +325,7 @@ def test_execute_update_w_params_wo_param_types(self):
         with self.assertRaises(ValueError):
             transaction.execute_update(DML_QUERY_WITH_PARAM, PARAMS)
 
-    def _execute_update_helper(self, partition=None, count=0):
+    def _execute_update_helper(self, count=0):
         from google.protobuf.struct_pb2 import Struct
         from google.cloud.spanner_v1.proto.result_set_pb2 import (
             ResultSet, ResultSetStats)
@@ -334,10 +334,7 @@ def _execute_update_helper(self, partition=None, count=0):
         from google.cloud.spanner_v1._helpers import _make_value_pb
 
         MODE = 2  # PROFILE
-        stats_pb = ResultSetStats(
-            query_stats=Struct(fields={
-                'rows_affected': _make_value_pb(1),
-            }))
+        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)
@@ -346,11 +343,10 @@ def _execute_update_helper(self, partition=None, count=0):
         transaction._transaction_id = self.TRANSACTION_ID
         transaction._execute_sql_count = count
 
-        result = transaction.execute_update(
-            DML_QUERY_WITH_PARAM, PARAMS, PARAM_TYPES,
-            query_mode=MODE, partition=partition)
+        row_count = transaction.execute_update(
+            DML_QUERY_WITH_PARAM, PARAMS, PARAM_TYPES, query_mode=MODE)
 
-        self.assertEqual(result, stats_pb)
+        self.assertEqual(row_count, 1)
 
         expected_transaction = TransactionSelector(id=self.TRANSACTION_ID)
         expected_params = Struct(fields={
@@ -363,18 +359,17 @@ def _execute_update_helper(self, partition=None, count=0):
             params=expected_params,
             param_types=PARAM_TYPES,
             query_mode=MODE,
-            partition_token=partition,
             seqno=count,
             metadata=[('google-cloud-resource-prefix', database.name)],
         )
 
         self.assertEqual(transaction._execute_sql_count, count + 1)
 
-    def test_execute_update_w_count_wo_partition(self):
-        self._execute_update_helper(count=1)
+    def test_execute_update_new_transaction(self):
+        self._execute_update_helper()
 
-    def test_execute_update_wo_count_w_partition(self):
-        self._execute_update_helper(partition=b'FACEDACE')
+    def test_execute_update_w_count(self):
+        self._execute_update_helper(count=1)
 
     def test_context_mgr_success(self):
         import datetime