superset/tests/unit_tests/models/helpers_test.py

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# pylint: disable=import-outside-toplevel

from __future__ import annotations

from contextlib import contextmanager
from typing import TYPE_CHECKING

import pytest
from pytest_mock import MockerFixture
from sqlalchemy import create_engine
from sqlalchemy.orm.session import Session
from sqlalchemy.pool import StaticPool

if TYPE_CHECKING:
    from superset.models.core import Database


@pytest.fixture()
def database(mocker: MockerFixture, session: Session) -> Database:
    from superset.connectors.sqla.models import SqlaTable
    from superset.models.core import Database

    SqlaTable.metadata.create_all(session.get_bind())

    engine = create_engine(
        "sqlite://",
        connect_args={"check_same_thread": False},
        poolclass=StaticPool,
    )
    database = Database(database_name="db", sqlalchemy_uri="sqlite://")

    connection = engine.raw_connection()
    connection.execute("CREATE TABLE t (a INTEGER, b TEXT)")
    connection.execute("INSERT INTO t VALUES (1, 'Alice')")
    connection.execute("INSERT INTO t VALUES (NULL, 'Bob')")
    connection.commit()

    # since we're using an in-memory SQLite database, make sure we always
    # return the same engine where the table was created
    @contextmanager
    def mock_get_sqla_engine():
        yield engine

    mocker.patch.object(
        database,
        "get_sqla_engine",
        new=mock_get_sqla_engine,
    )

    return database


def test_values_for_column(database: Database) -> None:
    """
    Test the `values_for_column` method.

    NULL values should be returned as `None`, not `np.nan`, since NaN cannot be
    serialized to JSON.
    """
    from superset.connectors.sqla.models import SqlaTable, TableColumn

    table = SqlaTable(
        database=database,
        schema=None,
        table_name="t",
        columns=[TableColumn(column_name="a")],
    )
    assert table.values_for_column("a") == [1, None]


def test_values_for_column_calculated(
    mocker: MockerFixture,
    database: Database,
) -> None:
    """
    Test that calculated columns work.
    """
    from superset.connectors.sqla.models import SqlaTable, TableColumn

    table = SqlaTable(
        database=database,
        schema=None,
        table_name="t",
        columns=[
            TableColumn(
                column_name="starts_with_A",
                expression="CASE WHEN b LIKE 'A%' THEN 'yes' ELSE 'nope' END",
            )
        ],
    )
    assert table.values_for_column("starts_with_A") == ["yes", "nope"]


def test_values_for_column_double_percents(
    mocker: MockerFixture,
    database: Database,
) -> None:
    """
    Test the behavior of `double_percents`.
    """
    from superset.connectors.sqla.models import SqlaTable, TableColumn

    with database.get_sqla_engine() as engine:
        engine.dialect.identifier_preparer._double_percents = "pyformat"

    table = SqlaTable(
        database=database,
        schema=None,
        table_name="t",
        columns=[
            TableColumn(
                column_name="starts_with_A",
                expression="CASE WHEN b LIKE 'A%' THEN 'yes' ELSE 'nope' END",
            )
        ],
    )

    mutate_sql_based_on_config = mocker.patch.object(
        database,
        "mutate_sql_based_on_config",
        side_effect=lambda sql: sql,
    )
    pd = mocker.patch("superset.models.helpers.pd")

    table.values_for_column("starts_with_A")

    # make sure the SQL originally had double percents
    mutate_sql_based_on_config.assert_called_with(
        "SELECT DISTINCT CASE WHEN b LIKE 'A%%' THEN 'yes' ELSE 'nope' END "
        "AS column_values \nFROM t\n LIMIT 10000 OFFSET 0"
    )
    # make sure final query has single percents
    with database.get_sqla_engine() as engine:
        pd.read_sql_query.assert_called_with(
            sql=(
                "SELECT DISTINCT CASE WHEN b LIKE 'A%' THEN 'yes' ELSE 'nope' END "
                "AS column_values \nFROM t\n LIMIT 10000 OFFSET 0"
            ),
            con=engine,
        )