chore: add label job sample

samples/snippets/label_job.py

@@ -0,0 +1,36 @@
+# Copyright 2025 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
+#
+#     https://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.
+
+
+def label_job() -> None:
+    # [START bigquery_label_job]
+    from google.cloud import bigquery
+
+    client = bigquery.Client()
+
+    sql = """
+        SELECT corpus
+        FROM `bigquery-public-data.samples.shakespeare`
+        GROUP BY corpus;
+    """
+    labels = {"color": "green"}
+
+    config = bigquery.QueryJobConfig()
+    config.labels = labels
+    location = "us"
+    job = client.query(sql, location=location, job_config=config)
+    job_id = job.job_id
+
+    print(f"Added {job.labels} to {job_id}.")
+    # [END bigquery_label_job]

samples/snippets/label_job_test.py

@@ -0,0 +1,31 @@
+# Copyright 2025 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
+#
+#     https://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 typing
+
+import label_job  # type: ignore
+
+
+if typing.TYPE_CHECKING:
+    import pytest
+
+
+def test_label_job(
+    capsys: "pytest.CaptureFixture[str]",
+) -> None:
+    label_job.label_job()
+
+    out, _ = capsys.readouterr()
+    assert "color" in out
+    assert "green" in out