datasource_tests.py

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# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you 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
#
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#
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"""Unit tests for Superset"""

from contextlib import contextmanager
from datetime import datetime, timedelta
from unittest import mock

import prison
import pytest

from superset import app, db
from superset.commands.dataset.exceptions import DatasetNotFoundError
from superset.common.utils.query_cache_manager import QueryCacheManager
from superset.connectors.sqla.models import (  # noqa: F401
    SqlaTable,
    SqlMetric,
    TableColumn,
)
from superset.constants import CacheRegion
from superset.daos.exceptions import DatasourceNotFound, DatasourceTypeNotSupportedError
from superset.exceptions import SupersetGenericDBErrorException
from superset.models.core import Database
from superset.utils import json
from superset.utils.core import backend, get_example_default_schema  # noqa: F401
from superset.utils.database import (  # noqa: F401
    get_example_database,
    get_main_database,
)
from tests.integration_tests.base_tests import db_insert_temp_object, SupersetTestCase
from tests.integration_tests.conftest import with_feature_flags
from tests.integration_tests.constants import ADMIN_USERNAME
from tests.integration_tests.fixtures.birth_names_dashboard import (
    load_birth_names_dashboard_with_slices,  # noqa: F401
    load_birth_names_data,  # noqa: F401
)
from tests.integration_tests.fixtures.datasource import get_datasource_post


@contextmanager
def create_test_table_context(database: Database):
    schema = get_example_default_schema()
    full_table_name = f"{schema}.test_table" if schema else "test_table"

    with database.get_sqla_engine() as engine:
        engine.execute(
            f"CREATE TABLE IF NOT EXISTS {full_table_name} AS SELECT 1 as first, 2 as second"
        )
        engine.execute(f"INSERT INTO {full_table_name} (first, second) VALUES (1, 2)")
        engine.execute(f"INSERT INTO {full_table_name} (first, second) VALUES (3, 4)")

    yield db.session

    with database.get_sqla_engine() as engine:
        engine.execute(f"DROP TABLE {full_table_name}")


@contextmanager
def create_and_cleanup_table(table=None):
    if table is None:
        table = SqlaTable(
            table_name="dummy_sql_table",
            database=get_example_database(),
            schema=get_example_default_schema(),
            sql="select 123 as intcol, 'abc' as strcol",
        )
    db.session.add(table)
    db.session.commit()
    try:
        yield table
    finally:
        db.session.delete(table)
        db.session.commit()


class TestDatasource(SupersetTestCase):
    def setUp(self):
        db.session.begin(subtransactions=True)

    def tearDown(self):
        db.session.rollback()
        super().tearDown()

    @pytest.mark.usefixtures("load_birth_names_dashboard_with_slices")
    def test_external_metadata_for_physical_table(self):
        self.login(ADMIN_USERNAME)
        tbl = self.get_table(name="birth_names")
        url = f"/datasource/external_metadata/table/{tbl.id}/"
        resp = self.get_json_resp(url)
        col_names = {o.get("column_name") for o in resp}
        assert col_names == {
            "num_boys",
            "num",
            "gender",
            "name",
            "ds",
            "state",
            "num_girls",
        }

    def test_always_filter_main_dttm(self):
        database = get_example_database()

        sql = f"SELECT DATE() as default_dttm, DATE() as additional_dttm, 1 as metric;"  # noqa: F541
        if database.backend == "sqlite":
            pass
        elif database.backend in ["postgresql", "mysql"]:
            sql = sql.replace("DATE()", "NOW()")
        else:
            return

        query_obj = {
            "columns": ["metric"],
            "filter": [],
            "from_dttm": datetime.now() - timedelta(days=1),
            "granularity": "additional_dttm",
            "orderby": [],
            "to_dttm": datetime.now() + timedelta(days=1),
            "series_columns": [],
            "row_limit": 1000,
            "row_offset": 0,
        }
        table = SqlaTable(
            table_name="dummy_sql_table",
            database=database,
            schema=get_example_default_schema(),
            main_dttm_col="default_dttm",
            columns=[
                TableColumn(column_name="default_dttm", type="DATETIME", is_dttm=True),
                TableColumn(
                    column_name="additional_dttm", type="DATETIME", is_dttm=True
                ),
            ],
            sql=sql,
        )

        with create_and_cleanup_table(table):
            table.always_filter_main_dttm = False
            result = str(table.get_sqla_query(**query_obj).sqla_query.whereclause)
            assert "default_dttm" not in result and "additional_dttm" in result

            table.always_filter_main_dttm = True
            result = str(table.get_sqla_query(**query_obj).sqla_query.whereclause)
            assert "default_dttm" in result and "additional_dttm" in result

    def test_external_metadata_for_virtual_table(self):
        self.login(ADMIN_USERNAME)

        with create_and_cleanup_table() as table:
            url = f"/datasource/external_metadata/table/{table.id}/"
            resp = self.get_json_resp(url)
            assert {o.get("column_name") for o in resp} == {"intcol", "strcol"}

    @pytest.mark.usefixtures("load_birth_names_dashboard_with_slices")
    def test_external_metadata_by_name_for_physical_table(self):
        self.login(ADMIN_USERNAME)
        tbl = self.get_table(name="birth_names")
        params = prison.dumps(
            {
                "datasource_type": "table",
                "database_name": tbl.database.database_name,
                "schema_name": tbl.schema,
                "table_name": tbl.table_name,
                "normalize_columns": tbl.normalize_columns,
                "always_filter_main_dttm": tbl.always_filter_main_dttm,
            }
        )
        url = f"/datasource/external_metadata_by_name/?q={params}"
        resp = self.get_json_resp(url)
        col_names = {o.get("column_name") for o in resp}
        assert col_names == {
            "num_boys",
            "num",
            "gender",
            "name",
            "ds",
            "state",
            "num_girls",
        }

    def test_external_metadata_by_name_for_virtual_table(self):
        self.login(ADMIN_USERNAME)
        with create_and_cleanup_table() as tbl:
            params = prison.dumps(
                {
                    "datasource_type": "table",
                    "database_name": tbl.database.database_name,
                    "schema_name": tbl.schema,
                    "table_name": tbl.table_name,
                    "normalize_columns": tbl.normalize_columns,
                    "always_filter_main_dttm": tbl.always_filter_main_dttm,
                }
            )
            url = f"/datasource/external_metadata_by_name/?q={params}"
            resp = self.get_json_resp(url)
            assert {o.get("column_name") for o in resp} == {"intcol", "strcol"}

    def test_external_metadata_by_name_for_virtual_table_uses_mutator(self):
        self.login(ADMIN_USERNAME)
        with create_and_cleanup_table() as tbl:
            app.config["SQL_QUERY_MUTATOR"] = (
                lambda sql, **kwargs: "SELECT 456 as intcol, 'def' as mutated_strcol"
            )

            params = prison.dumps(
                {
                    "datasource_type": "table",
                    "database_name": tbl.database.database_name,
                    "schema_name": tbl.schema,
                    "table_name": tbl.table_name,
                    "normalize_columns": tbl.normalize_columns,
                    "always_filter_main_dttm": tbl.always_filter_main_dttm,
                }
            )
            url = f"/datasource/external_metadata_by_name/?q={params}"
            resp = self.get_json_resp(url)
            assert {o.get("column_name") for o in resp} == {"intcol", "mutated_strcol"}
            app.config["SQL_QUERY_MUTATOR"] = None

    def test_external_metadata_by_name_from_sqla_inspector(self):
        self.login(ADMIN_USERNAME)
        example_database = get_example_database()
        with create_test_table_context(example_database):
            params = prison.dumps(
                {
                    "datasource_type": "table",
                    "database_name": example_database.database_name,
                    "table_name": "test_table",
                    "schema_name": get_example_default_schema(),
                    "normalize_columns": False,
                    "always_filter_main_dttm": False,
                }
            )
            url = f"/datasource/external_metadata_by_name/?q={params}"
            resp = self.get_json_resp(url)
            col_names = {o.get("column_name") for o in resp}
            assert col_names == {"first", "second"}

        # No databases found
        params = prison.dumps(
            {
                "datasource_type": "table",
                "database_name": "foo",
                "table_name": "bar",
                "normalize_columns": False,
                "always_filter_main_dttm": False,
            }
        )
        url = f"/datasource/external_metadata_by_name/?q={params}"
        resp = self.client.get(url)
        assert resp.status_code == DatasetNotFoundError.status
        assert (
            json.loads(resp.data.decode("utf-8")).get("error")
            == DatasetNotFoundError.message
        )

        # No table found
        params = prison.dumps(
            {
                "datasource_type": "table",
                "database_name": example_database.database_name,
                "table_name": "fooooooooobarrrrrr",
                "normalize_columns": False,
                "always_filter_main_dttm": False,
            }
        )
        url = f"/datasource/external_metadata_by_name/?q={params}"
        resp = self.client.get(url)
        assert resp.status_code == DatasetNotFoundError.status
        assert (
            json.loads(resp.data.decode("utf-8")).get("error")
            == DatasetNotFoundError.message
        )

        # invalid query params
        params = prison.dumps(
            {
                "datasource_type": "table",
            }
        )
        url = f"/datasource/external_metadata_by_name/?q={params}"
        resp = self.get_json_resp(url)
        assert "error" in resp

    def test_external_metadata_for_virtual_table_template_params(self):
        self.login(ADMIN_USERNAME)
        table = SqlaTable(
            table_name="dummy_sql_table_with_template_params",
            database=get_example_database(),
            schema=get_example_default_schema(),
            sql="select {{ foo }} as intcol",
            template_params=json.dumps({"foo": "123"}),
        )
        with create_and_cleanup_table(table) as tbl:
            url = f"/datasource/external_metadata/table/{tbl.id}/"
            resp = self.get_json_resp(url)
            assert {o.get("column_name") for o in resp} == {"intcol"}

    def test_external_metadata_for_malicious_virtual_table(self):
        self.login(ADMIN_USERNAME)
        table = SqlaTable(
            table_name="malicious_sql_table",
            database=get_example_database(),
            schema=get_example_default_schema(),
            sql="delete table birth_names",
        )
        with db_insert_temp_object(table):
            url = f"/datasource/external_metadata/table/{table.id}/"
            resp = self.get_json_resp(url)
            assert resp["error"] == "Only `SELECT` statements are allowed"

    def test_external_metadata_for_multistatement_virtual_table(self):
        self.login(ADMIN_USERNAME)
        table = SqlaTable(
            table_name="multistatement_sql_table",
            database=get_example_database(),
            schema=get_example_default_schema(),
            sql="select 123 as intcol, 'abc' as strcol;"
            "select 123 as intcol, 'abc' as strcol",
        )
        with db_insert_temp_object(table):
            url = f"/datasource/external_metadata/table/{table.id}/"
            resp = self.get_json_resp(url)
            assert resp["error"] == "Only single queries supported"

    @pytest.mark.usefixtures("load_birth_names_dashboard_with_slices")
    @mock.patch("superset.connectors.sqla.models.SqlaTable.external_metadata")
    def test_external_metadata_error_return_400(self, mock_get_datasource):
        self.login(ADMIN_USERNAME)
        tbl = self.get_table(name="birth_names")
        url = f"/datasource/external_metadata/table/{tbl.id}/"

        mock_get_datasource.side_effect = SupersetGenericDBErrorException("oops")

        pytest.raises(
            SupersetGenericDBErrorException,
            lambda: db.session.query(SqlaTable)
            .filter_by(id=tbl.id)
            .one_or_none()
            .external_metadata(),
        )

        resp = self.client.get(url)
        assert resp.status_code == 400

    def compare_lists(self, l1, l2, key):
        l2_lookup = {o.get(key): o for o in l2}
        for obj1 in l1:
            obj2 = l2_lookup.get(obj1.get(key))
            for k in obj1:
                if k not in "id" and obj1.get(k):
                    assert obj1.get(k) == obj2.get(k)

    def test_save(self):
        self.login(ADMIN_USERNAME)
        tbl_id = self.get_table(name="birth_names").id

        datasource_post = get_datasource_post()
        datasource_post["id"] = tbl_id
        datasource_post["owners"] = [1]
        data = dict(data=json.dumps(datasource_post))
        resp = self.get_json_resp("/datasource/save/", data)
        for k in datasource_post:
            if k == "columns":
                self.compare_lists(datasource_post[k], resp[k], "column_name")
            elif k == "metrics":
                self.compare_lists(datasource_post[k], resp[k], "metric_name")
            elif k == "database":
                assert resp[k]["id"] == datasource_post[k]["id"]
            elif k == "owners":
                assert [o["id"] for o in resp[k]] == datasource_post["owners"]
            else:
                assert resp[k] == datasource_post[k]

    def test_save_default_endpoint_validation_success(self):
        self.login(ADMIN_USERNAME)
        tbl_id = self.get_table(name="birth_names").id

        datasource_post = get_datasource_post()
        datasource_post["id"] = tbl_id
        datasource_post["owners"] = [1]
        datasource_post["default_endpoint"] = "http://localhost/superset/1"
        data = dict(data=json.dumps(datasource_post))
        resp = self.client.post("/datasource/save/", data=data)
        assert resp.status_code == 200

    def save_datasource_from_dict(self, datasource_post):
        data = dict(data=json.dumps(datasource_post))
        resp = self.get_json_resp("/datasource/save/", data)
        return resp

    @pytest.mark.usefixtures("load_birth_names_dashboard_with_slices")
    def test_change_database(self):
        admin_user = self.get_user("admin")
        self.login(admin_user.username)
        tbl = self.get_table(name="birth_names")
        tbl_id = tbl.id
        db_id = tbl.database_id
        datasource_post = get_datasource_post()
        datasource_post["id"] = tbl_id
        datasource_post["owners"] = [admin_user.id]

        new_db = self.create_fake_db()
        datasource_post["database"]["id"] = new_db.id
        resp = self.save_datasource_from_dict(datasource_post)
        assert resp["database"]["id"] == new_db.id

        datasource_post["database"]["id"] = db_id
        resp = self.save_datasource_from_dict(datasource_post)
        assert resp["database"]["id"] == db_id

        self.delete_fake_db()

    def test_save_duplicate_key(self):
        admin_user = self.get_user("admin")
        self.login(admin_user.username)
        tbl_id = self.get_table(name="birth_names").id

        datasource_post = get_datasource_post()
        datasource_post["id"] = tbl_id
        datasource_post["owners"] = [admin_user.id]
        datasource_post["columns"].extend(
            [
                {
                    "column_name": "<new column>",
                    "filterable": True,
                    "groupby": True,
                    "expression": "<enter SQL expression here>",
                    "id": "somerandomid",
                },
                {
                    "column_name": "<new column>",
                    "filterable": True,
                    "groupby": True,
                    "expression": "<enter SQL expression here>",
                    "id": "somerandomid2",
                },
            ]
        )
        data = dict(data=json.dumps(datasource_post))
        resp = self.get_json_resp("/datasource/save/", data, raise_on_error=False)
        assert "Duplicate column name(s): <new column>" in resp["error"]

    def test_get_datasource(self):
        admin_user = self.get_user("admin")
        self.login(admin_user.username)
        tbl = self.get_table(name="birth_names")

        datasource_post = get_datasource_post()
        datasource_post["id"] = tbl.id
        datasource_post["owners"] = [admin_user.id]
        data = dict(data=json.dumps(datasource_post))
        self.get_json_resp("/datasource/save/", data)
        url = f"/datasource/get/{tbl.type}/{tbl.id}/"
        resp = self.get_json_resp(url)
        assert resp.get("type") == "table"
        col_names = {o.get("column_name") for o in resp["columns"]}
        assert col_names == {
            "num_boys",
            "num",
            "gender",
            "name",
            "ds",
            "state",
            "num_girls",
            "num_california",
        }

    def test_get_datasource_with_health_check(self):
        def my_check(datasource):
            return "Warning message!"

        app.config["DATASET_HEALTH_CHECK"] = my_check
        self.login(ADMIN_USERNAME)
        tbl = self.get_table(name="birth_names")
        datasource = db.session.query(SqlaTable).filter_by(id=tbl.id).one_or_none()
        assert datasource.health_check_message == "Warning message!"
        app.config["DATASET_HEALTH_CHECK"] = None

    def test_get_datasource_failed(self):
        from superset.daos.datasource import DatasourceDAO

        pytest.raises(
            DatasourceNotFound,
            lambda: DatasourceDAO.get_datasource("table", 9999999),
        )

        self.login(ADMIN_USERNAME)
        resp = self.get_json_resp("/datasource/get/table/500000/", raise_on_error=False)
        assert resp.get("error") == "Datasource does not exist"

    def test_get_datasource_invalid_datasource_failed(self):
        from superset.daos.datasource import DatasourceDAO

        pytest.raises(
            DatasourceTypeNotSupportedError,
            lambda: DatasourceDAO.get_datasource("druid", 9999999),
        )

        self.login(ADMIN_USERNAME)
        resp = self.get_json_resp("/datasource/get/druid/500000/", raise_on_error=False)
        assert resp.get("error") == "'druid' is not a valid DatasourceType"


def test_get_samples(test_client, login_as_admin, virtual_dataset):
    """
    Dataset API: Test get dataset samples
    """
    # 1. should cache data
    uri = (
        f"/datasource/samples?datasource_id={virtual_dataset.id}&datasource_type=table"
    )
    # feeds data
    test_client.post(uri, json={})
    # get from cache
    rv = test_client.post(uri, json={})
    assert rv.status_code == 200
    assert len(rv.json["result"]["data"]) == 10
    assert QueryCacheManager.has(
        rv.json["result"]["cache_key"],
        region=CacheRegion.DATA,
    )
    assert rv.json["result"]["is_cached"]

    # 2. should read through cache data
    uri2 = f"/datasource/samples?datasource_id={virtual_dataset.id}&datasource_type=table&force=true"
    # feeds data
    test_client.post(uri2, json={})
    # force query
    rv2 = test_client.post(uri2, json={})
    assert rv2.status_code == 200
    assert len(rv2.json["result"]["data"]) == 10
    assert QueryCacheManager.has(
        rv2.json["result"]["cache_key"],
        region=CacheRegion.DATA,
    )
    assert not rv2.json["result"]["is_cached"]

    # 3. data precision
    assert "colnames" in rv2.json["result"]
    assert "coltypes" in rv2.json["result"]
    assert "data" in rv2.json["result"]

    sql = (
        f"select * from ({virtual_dataset.sql}) as tbl "
        f'limit {app.config["SAMPLES_ROW_LIMIT"]}'
    )
    eager_samples = virtual_dataset.database.get_df(sql)

    # the col3 is Decimal
    eager_samples["col3"] = eager_samples["col3"].apply(float)
    eager_samples = eager_samples.to_dict(orient="records")
    assert eager_samples == rv2.json["result"]["data"]


def test_get_samples_with_incorrect_cc(test_client, login_as_admin, virtual_dataset):
    TableColumn(
        column_name="DUMMY CC",
        type="VARCHAR(255)",
        table=virtual_dataset,
        expression="INCORRECT SQL",
    )

    uri = (
        f"/datasource/samples?datasource_id={virtual_dataset.id}&datasource_type=table"
    )
    rv = test_client.post(uri, json={})
    assert rv.status_code == 422

    assert "error" in rv.json
    if virtual_dataset.database.db_engine_spec.engine_name == "PostgreSQL":
        assert "INCORRECT SQL" in rv.json.get("error")


@with_feature_flags(ALLOW_ADHOC_SUBQUERY=True)
def test_get_samples_on_physical_dataset(test_client, login_as_admin, physical_dataset):
    uri = (
        f"/datasource/samples?datasource_id={physical_dataset.id}&datasource_type=table"
    )
    rv = test_client.post(uri, json={})
    assert rv.status_code == 200
    assert QueryCacheManager.has(
        rv.json["result"]["cache_key"], region=CacheRegion.DATA
    )
    assert len(rv.json["result"]["data"]) == 10


def test_get_samples_with_filters(test_client, login_as_admin, virtual_dataset):
    uri = (
        f"/datasource/samples?datasource_id={virtual_dataset.id}&datasource_type=table"
    )
    rv = test_client.post(uri, json=None)
    assert rv.status_code == 415

    rv = test_client.post(uri, json={})
    assert rv.status_code == 200

    rv = test_client.post(uri, json={"foo": "bar"})
    assert rv.status_code == 400

    rv = test_client.post(
        uri, json={"filters": [{"col": "col1", "op": "INVALID", "val": 0}]}
    )
    assert rv.status_code == 400

    rv = test_client.post(
        uri,
        json={
            "filters": [
                {"col": "col2", "op": "==", "val": "a"},
                {"col": "col1", "op": "==", "val": 0},
            ]
        },
    )
    assert rv.status_code == 200
    assert rv.json["result"]["colnames"] == [
        "col1",
        "col2",
        "col3",
        "col4",
        "col5",
        "col6",
    ]
    assert rv.json["result"]["rowcount"] == 1

    # empty results
    rv = test_client.post(
        uri,
        json={
            "filters": [
                {"col": "col2", "op": "==", "val": "x"},
            ]
        },
    )
    assert rv.status_code == 200
    assert rv.json["result"]["colnames"] == []
    assert rv.json["result"]["rowcount"] == 0


@with_feature_flags(ALLOW_ADHOC_SUBQUERY=True)
def test_get_samples_with_time_filter(test_client, login_as_admin, physical_dataset):
    uri = (
        f"/datasource/samples?datasource_id={physical_dataset.id}&datasource_type=table"
    )
    payload = {
        "granularity": "col5",
        "time_range": "2000-01-02 : 2000-01-04",
    }
    rv = test_client.post(uri, json=payload)
    assert len(rv.json["result"]["data"]) == 2
    if physical_dataset.database.backend != "sqlite":
        assert [row["col5"] for row in rv.json["result"]["data"]] == [
            946771200000.0,  # 2000-01-02 00:00:00
            946857600000.0,  # 2000-01-03 00:00:00
        ]
    assert rv.json["result"]["page"] == 1
    assert rv.json["result"]["per_page"] == app.config["SAMPLES_ROW_LIMIT"]
    assert rv.json["result"]["total_count"] == 2


@with_feature_flags(ALLOW_ADHOC_SUBQUERY=True)
def test_get_samples_with_multiple_filters(
    test_client, login_as_admin, physical_dataset
):
    # 1. empty response
    uri = (
        f"/datasource/samples?datasource_id={physical_dataset.id}&datasource_type=table"
    )
    payload = {
        "granularity": "col5",
        "time_range": "2000-01-02 : 2000-01-04",
        "filters": [
            {"col": "col4", "op": "IS NOT NULL"},
        ],
    }
    rv = test_client.post(uri, json=payload)
    assert len(rv.json["result"]["data"]) == 0

    # 2. adhoc filters, time filters, and custom where
    payload = {
        "granularity": "col5",
        "time_range": "2000-01-02 : 2000-01-04",
        "filters": [
            {"col": "col2", "op": "==", "val": "c"},
        ],
        "extras": {"where": "col3 = 1.2 and col4 is null"},
    }
    rv = test_client.post(uri, json=payload)
    assert len(rv.json["result"]["data"]) == 1
    assert rv.json["result"]["total_count"] == 1
    assert "2000-01-02" in rv.json["result"]["query"]
    assert "2000-01-04" in rv.json["result"]["query"]
    assert "col3 = 1.2" in rv.json["result"]["query"]
    assert "col4 is null" in rv.json["result"]["query"]
    assert "col2 = 'c'" in rv.json["result"]["query"]


def test_get_samples_pagination(test_client, login_as_admin, virtual_dataset):
    # 1. default page, per_page and total_count
    uri = (
        f"/datasource/samples?datasource_id={virtual_dataset.id}&datasource_type=table"
    )
    rv = test_client.post(uri, json={})
    assert rv.json["result"]["page"] == 1
    assert rv.json["result"]["per_page"] == app.config["SAMPLES_ROW_LIMIT"]
    assert rv.json["result"]["total_count"] == 10

    # 2. incorrect per_page
    per_pages = (app.config["SAMPLES_ROW_LIMIT"] + 1, 0, "xx")
    for per_page in per_pages:
        uri = f"/datasource/samples?datasource_id={virtual_dataset.id}&datasource_type=table&per_page={per_page}"
        rv = test_client.post(uri, json={})
        assert rv.status_code == 400

    # 3. incorrect page or datasource_type
    uri = f"/datasource/samples?datasource_id={virtual_dataset.id}&datasource_type=table&page=xx"
    rv = test_client.post(uri, json={})
    assert rv.status_code == 400

    uri = f"/datasource/samples?datasource_id={virtual_dataset.id}&datasource_type=xx"
    rv = test_client.post(uri, json={})
    assert rv.status_code == 400

    # 4. turning pages
    uri = f"/datasource/samples?datasource_id={virtual_dataset.id}&datasource_type=table&per_page=2&page=1"
    rv = test_client.post(uri, json={})
    assert rv.json["result"]["page"] == 1
    assert rv.json["result"]["per_page"] == 2
    assert rv.json["result"]["total_count"] == 10
    assert [row["col1"] for row in rv.json["result"]["data"]] == [0, 1]

    uri = f"/datasource/samples?datasource_id={virtual_dataset.id}&datasource_type=table&per_page=2&page=2"
    rv = test_client.post(uri, json={})
    assert rv.json["result"]["page"] == 2
    assert rv.json["result"]["per_page"] == 2
    assert rv.json["result"]["total_count"] == 10
    assert [row["col1"] for row in rv.json["result"]["data"]] == [2, 3]

    # 5. Exceeding the maximum pages
    uri = f"/datasource/samples?datasource_id={virtual_dataset.id}&datasource_type=table&per_page=2&page=6"
    rv = test_client.post(uri, json={})
    assert rv.json["result"]["page"] == 6
    assert rv.json["result"]["per_page"] == 2
    assert rv.json["result"]["total_count"] == 10
    assert [row["col1"] for row in rv.json["result"]["data"]] == []