docs: create sample to write schema file from table (googleapis#1439)

* docs: create sample to write schema file from table

* Apply suggestions from code review

Co-authored-by: Tim Swast <swast@google.com>

samples/snippets/get_table_make_schema.py

@@ -0,0 +1,47 @@
+# Copyright 2022 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 get_table_make_schema(table_id: str, schema_path: str) -> None:
+    orig_table_id = table_id
+    orig_schema_path = schema_path
+    # [START bigquery_schema_file_get]
+    from google.cloud import bigquery
+
+    client = bigquery.Client()
+
+    # TODO(dev): Change the table_id variable to the full name of the
+    # table you want to get schema from.
+    table_id = "your-project.your_dataset.your_table_name"
+
+    # TODO(dev): Change schema_path variable to the path
+    # of your schema file.
+    schema_path = "path/to/schema.json"
+    # [END bigquery_schema_file_get]
+    table_id = orig_table_id
+    schema_path = orig_schema_path
+    # [START bigquery_schema_file_get]
+    table = client.get_table(table_id)  # Make an API request.
+
+    # Write a schema file to schema_path with the schema_to_json method.
+    client.schema_to_json(table.schema, schema_path)
+
+    with open(schema_path, "r", encoding="utf-8") as schema_file:
+        schema_contents = schema_file.read()
+
+    # View table properties
+    print(f"Got table '{table.project}.{table.dataset_id}.{table.table_id}'.")
+    print(f"Table schema: {schema_contents}")
+
+    # [END bigquery_schema_file_get]

samples/snippets/get_table_make_schema_test.py

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+# Copyright 2022 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 get_table_make_schema
+
+if typing.TYPE_CHECKING:
+    import pathlib
+
+    import pytest
+
+
+def test_get_table_make_schema(
+    capsys: "pytest.CaptureFixture[str]",
+    table_id: str,
+    tmp_path: "pathlib.Path",
+) -> None:
+    schema_path = str(tmp_path / "test_schema.json")
+
+    get_table_make_schema.get_table_make_schema(table_id, schema_path)
+
+    out, _ = capsys.readouterr()
+    assert "Got table" in out
+    assert table_id in out