docs: add code sample snippets for welcome page documentation

Author: shuoweil

packages/bigframes/samples/snippets/samples_test.py

@@ -0,0 +1,138 @@
+# 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.
+
+
+def test_query_standard_sql():
+    # [START bigquery_bigframes_query]
+    import bigframes.pandas as bpd
+
+    # Set partial ordering mode as the default configuration for BigQuery DataFrames.
+    bpd.options.bigquery.ordering_mode = "partial"
+
+    sql = """
+    SELECT name FROM `bigquery-public-data.usa_names.usa_1910_current`
+    WHERE state = 'TX'
+    LIMIT 100
+    """
+
+    # Run a query alongside existing SQL. The project will be determined from default credentials.
+    df = bpd.read_gbq(sql)
+
+    # Run a query after explicitly specifying a project.
+    bpd.options.bigquery.project = "your-project-id"
+    df = bpd.read_gbq(sql)
+    # [END bigquery_bigframes_query]
+    assert df is not None
+
+
+def test_query_legacy_sql():
+    # [START bigquery_bigframes_query_legacy]
+    import bigframes.pandas as bpd
+
+    # Set partial ordering mode as the default configuration for BigQuery DataFrames.
+    bpd.options.bigquery.ordering_mode = "partial"
+
+    sql = """
+    SELECT name FROM [bigquery-public-data:usa_names.usa_1910_current]
+    WHERE state = 'TX'
+    LIMIT 100
+    """
+
+    # Run a query using legacy SQL syntax.
+    query_config = {"query": {"useLegacySql": True}}
+    df = bpd.read_gbq(sql, configuration=query_config)
+    # [END bigquery_bigframes_query_legacy]
+    assert df is not None
+
+
+def test_query_bqstorage():
+    # [START bigquery_bigframes_query_bqstorage]
+    import bigframes.pandas as bpd
+
+    # Set partial ordering mode as the default configuration for BigQuery DataFrames.
+    bpd.options.bigquery.ordering_mode = "partial"
+
+    sql = """
+    SELECT name FROM `bigquery-public-data.usa_names.usa_1910_current`
+    WHERE state = 'TX'
+    LIMIT 100
+    """
+
+    # Read query results into a server-side DataFrame without downloading data.
+    df = bpd.read_gbq(sql)
+
+    # When downloading results to an in-memory pandas DataFrame, bigquery-dataframes
+    # automatically uses the BigQuery Storage API if installed.
+    pandas_df = df.to_pandas()
+    # [END bigquery_bigframes_query_bqstorage]
+    assert pandas_df is not None
+
+
+def test_query_parameters():
+    # [START bigquery_bigframes_query_parameters]
+    import bigframes.pandas as bpd
+
+    # Set partial ordering mode as the default configuration for BigQuery DataFrames.
+    bpd.options.bigquery.ordering_mode = "partial"
+
+    sql = """
+    SELECT name FROM `bigquery-public-data.usa_names.usa_1910_current`
+    WHERE state = @state
+    LIMIT 100
+    """
+
+    query_config = {
+        "query": {
+            "parameterMode": "NAMED",
+            "queryParameters": [
+                {
+                    "name": "state",
+                    "parameterType": {"type": "STRING"},
+                    "parameterValue": {"value": "TX"},
+                }
+            ],
+        }
+    }
+
+    df = bpd.read_gbq(sql, configuration=query_config)
+    # [END bigquery_bigframes_query_parameters]
+    assert df is not None
+
+
+def test_upload_from_dataframe():
+    # [START bigquery_bigframes_upload_from_dataframe]
+    import pandas as pd
+
+    import bigframes.pandas as bpd
+
+    # Set partial ordering mode as the default configuration for BigQuery DataFrames.
+    bpd.options.bigquery.ordering_mode = "partial"
+
+    # Create a local pandas DataFrame.
+    df = pd.DataFrame(
+        {
+            "my_string": ["a", "b", "c"],
+            "my_int64": [1, 2, 3],
+            "my_float64": [4.0, 5.0, 6.0],
+        }
+    )
+
+    # Convert the local pandas DataFrame to a BigQuery DataFrame.
+    bq_df = bpd.read_pandas(df)
+
+    # Write the DataFrame to a BigQuery table.
+    table_id = "your-project.your_dataset.your_table_name"
+    bq_df.to_gbq(table_id, if_exists="replace")
+    # [END bigquery_bigframes_upload_from_dataframe]
+    assert bq_df is not None