Merge pull request #3116 from tseaver/3029-bigquery-systest-legacy_da…

…tatypes

Add system tests for legacy data types.

system_tests/bigquery.py

@@ -479,14 +479,54 @@ def _job_done(instance):
         # raise an error, and that the job completed (in the `retry()`
         # above).
 
+    def test_sync_query_w_legacy_sql_types(self):
+        import datetime
+        from google.cloud._helpers import UTC
+        naive = datetime.datetime(2016, 12, 5, 12, 41, 9)
+        stamp = '%s %s' % (naive.date().isoformat(), naive.time().isoformat())
+        zoned = naive.replace(tzinfo=UTC)
+        EXAMPLES = [
+            {
+                'sql': 'SELECT 1',
+                'expected': 1,
+            },
+            {
+                'sql': 'SELECT 1.3',
+                'expected': 1.3,
+            },
+            {
+                'sql': 'SELECT TRUE',
+                'expected': True,
+            },
+            {
+                'sql': 'SELECT "ABC"',
+                'expected': 'ABC',
+            },
+            {
+                'sql': 'SELECT CAST("foo" AS BYTES)',
+                'expected': b'foo',
+            },
+            {
+                'sql': 'SELECT CAST("%s" AS TIMESTAMP)' % (stamp,),
+                'expected': zoned,
+            },
+        ]
+        for example in EXAMPLES:
+            query = Config.CLIENT.run_sync_query(example['sql'])
+            query.use_legacy_sql = True
+            query.run()
+            self.assertEqual(len(query.rows), 1)
+            self.assertEqual(len(query.rows[0]), 1)
+            self.assertEqual(query.rows[0][0], example['expected'])
+
     def test_sync_query_w_standard_sql_types(self):
         import datetime
         from google.cloud._helpers import UTC
         from google.cloud.bigquery._helpers import ArrayQueryParameter
         from google.cloud.bigquery._helpers import ScalarQueryParameter
         from google.cloud.bigquery._helpers import StructQueryParameter
         naive = datetime.datetime(2016, 12, 5, 12, 41, 9)
-        stamp = "%s %s" % (naive.date().isoformat(), naive.time().isoformat())
+        stamp = '%s %s' % (naive.date().isoformat(), naive.time().isoformat())
         zoned = naive.replace(tzinfo=UTC)
         zoned_param = ScalarQueryParameter(
             name='zoned', type_='TIMESTAMP', value=zoned)