Allow timestamp strings in 'Table.insert_data'.

bigquery/google/cloud/bigquery/table.py

@@ -738,15 +738,20 @@ def insert_data(self,
         rows_info = []
         data = {'rows': rows_info}
 
+        def _convert_timestamp(value):
+            if isinstance(value, datetime.datetime):
+                value = _microseconds_from_datetime(value) * 1e-6
+            return value
+
         for index, row in enumerate(rows):
             row_info = {}
 
             for field, value in zip(self._schema, row):
-                if field.field_type == 'TIMESTAMP' and value is not None:
+                if field.field_type == 'TIMESTAMP':
                     # BigQuery stores TIMESTAMP data internally as a
                     # UNIX timestamp with microsecond precision.
                     # Specifies the number of seconds since the epoch.
-                    value = _microseconds_from_datetime(value) * 1e-6
+                    value = _convert_timestamp(value)
                 row_info[field.name] = value
 
             info = {'json': row_info}

bigquery/unit_tests/test_table.py

@@ -1296,6 +1296,7 @@ def test_insert_data_wo_schema(self):
     def test_insert_data_w_bound_client(self):
         import datetime
         from google.cloud._helpers import UTC
+        from google.cloud._helpers import _datetime_to_rfc3339
         from google.cloud._helpers import _microseconds_from_datetime
         from google.cloud.bigquery.table import SchemaField
 
@@ -1313,16 +1314,16 @@ def test_insert_data_w_bound_client(self):
         table = self._make_one(self.TABLE_NAME, dataset=dataset,
                                schema=[full_name, age, joined])
         ROWS = [
-            ('Phred Phlyntstone', 32, WHEN),
+            ('Phred Phlyntstone', 32, _datetime_to_rfc3339(WHEN)),
             ('Bharney Rhubble', 33, WHEN + datetime.timedelta(seconds=1)),
             ('Wylma Phlyntstone', 29, WHEN + datetime.timedelta(seconds=2)),
             ('Bhettye Rhubble', 27, None),
         ]
 
         def _row_data(row):
-            joined = None
-            if row[2] is not None:
-                joined = _microseconds_from_datetime(row[2]) * 1e-6
+            joined = row[2]
+            if isinstance(row[2], datetime.datetime):
+                joined = _microseconds_from_datetime(joined) * 1e-6
             return {'full_name': row[0],
                     'age': row[1],
                     'joined': joined}