ENH: Adding schema to GBQConnector

ENH: Schema outputs a list of dicts

Fixing Flake8

Author: mr-mcox

pandas_gbq/gbq.py

@@ -558,7 +558,9 @@ def load_data(self, dataframe, dataset_id, table_id, chunksize):
 
         self._print("\n")
 
-    def verify_schema(self, dataset_id, table_id, schema):
+    def schema(self, dataset_id, table_id):
+        """Retrieve the schema of the table"""
+
         try:
             from googleapiclient.errors import HttpError
         except:
@@ -574,15 +576,18 @@ def verify_schema(self, dataset_id, table_id, schema):
                               'type': field_remote['type']}
                              for field_remote in remote_schema['fields']]
 
-            fields_remote = set([json.dumps(field_remote)
-                                 for field_remote in remote_fields])
-            fields_local = set(json.dumps(field_local)
-                               for field_local in schema['fields'])
-
-            return fields_remote == fields_local
+            return remote_fields
         except HttpError as ex:
             self.process_http_error(ex)
 
+    def verify_schema(self, dataset_id, table_id, schema):
+        fields_remote = set([json.dumps(field)
+                             for field in self.schema(dataset_id, table_id)])
+        fields_local = set(json.dumps(field_local)
+                           for field_local in schema['fields'])
+
+        return fields_remote == fields_local
+
     def delete_and_recreate_table(self, dataset_id, table_id, table_schema):
         delay = 0
 

pandas_gbq/tests/test_gbq.py

@@ -19,9 +19,12 @@
 import pandas.util.testing as tm
 from pandas.compat.numpy import np_datetime64_compat
 
-PROJECT_ID = None
-PRIVATE_KEY_JSON_PATH = None
-PRIVATE_KEY_JSON_CONTENTS = None
+PROJECT_ID = os.environ.get('PROJECT_ID')
+PRIVATE_KEY_JSON_PATH = 'client_secrets.json'
+PRIVATE_KEY_JSON_CONTENTS = os.environ.get('SERVICE_ACCOUNT_KEY')
+# PROJECT_ID = None
+# PRIVATE_KEY_JSON_PATH = None
+# PRIVATE_KEY_JSON_CONTENTS = None
 
 TABLE_ID = 'new_test'
 
@@ -309,6 +312,7 @@ def test_get_application_default_credentials_returns_credentials(self):
 
 
 class TestGBQConnectorIntegrationWithServiceAccountKeyPath(tm.TestCase):
+
     def setUp(self):
         _setup_common()
 
@@ -340,6 +344,7 @@ def test_should_be_able_to_get_results_from_query(self):
 
 
 class TestGBQConnectorIntegrationWithServiceAccountKeyContents(tm.TestCase):
+
     def setUp(self):
         _setup_common()
 
@@ -1275,6 +1280,18 @@ def test_verify_schema_ignores_field_mode(self):
             self.dataset_prefix + "1", TABLE_ID + test_id, test_schema_2),
             'Expected schema to match')
 
+    def test_retrieve_schema(self):
+        test_id = "15"
+        test_schema = {'fields': [{'name': 'A', 'type': 'FLOAT'},
+                                  {'name': 'B', 'type': 'FLOAT'},
+                                  {'name': 'C', 'type': 'STRING'},
+                                  {'name': 'D', 'type': 'TIMESTAMP'}]}
+
+        self.table.create(TABLE_ID + test_id, test_schema)
+        actual = self.sut.schema(self.dataset_prefix + "1", TABLE_ID + test_id)
+        expected = test_schema['fields']
+        assert expected == actual, 'Expected schema used to create table'
+
     def test_list_dataset(self):
         dataset_id = self.dataset_prefix + "1"
         self.assertTrue(dataset_id in self.dataset.datasets(),