test: add system test for create_external_table

Author: GarrettWu

tests/system/large/bigquery/test_table.py

@@ -0,0 +1,36 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import bigframes.bigquery as bbq
+
+
+def test_create_external_table(session, dataset_id, bq_connection):
+    table_name = f"{dataset_id}.test_object_table"
+    uri = "gs://cloud-samples-data/bigquery/tutorials/cymbal-pets/images/*"
+
+    # Create the external table
+    table = bbq.create_external_table(
+        table_name,
+        connection_name=bq_connection,
+        options={"object_metadata": "SIMPLE", "uris": [uri]},
+        session=session,
+    )
+    assert table is not None
+
+    # Read the table to verify
+    import bigframes.pandas as bpd
+
+    bf_df = bpd.read_gbq(table_name)
+    pd_df = bf_df.to_pandas()
+    assert len(pd_df) > 0