langchain/tests/unit_tests/test_sql_database.py

# flake8: noqa=E501
"""Test SQL database wrapper."""

from sqlalchemy import Column, Integer, MetaData, String, Table, create_engine, insert

from langchain.sql_database import _TEMPLATE_PREFIX, SQLDatabase

metadata_obj = MetaData()

user = Table(
    "user",
    metadata_obj,
    Column("user_id", Integer, primary_key=True),
    Column("user_name", String(16), nullable=False),
)

company = Table(
    "company",
    metadata_obj,
    Column("company_id", Integer, primary_key=True),
    Column("company_location", String, nullable=False),
)


def test_table_info() -> None:
    """Test that table info is constructed properly."""
    engine = create_engine("sqlite:///:memory:")
    metadata_obj.create_all(engine)
    db = SQLDatabase(engine)
    output = db.table_info
    output = output[len(_TEMPLATE_PREFIX) :]
    expected_output = (
        "Table 'user' has columns: {'user_id': ['INTEGER'], 'user_name': ['VARCHAR(16)']}",
        "Table 'company' has columns: {'company_id': ['INTEGER'], 'company_location': ['VARCHAR']}",
    )
    assert sorted(output.split("\n")) == sorted(expected_output)


def test_table_info_w_sample_rows() -> None:
    """Test that table info is constructed properly."""
    engine = create_engine("sqlite:///:memory:")
    metadata_obj.create_all(engine)
    values = [
        {"user_id": 13, "user_name": "Harrison"},
        {"user_id": 14, "user_name": "Chase"},
    ]
    stmt = insert(user).values(values)
    with engine.begin() as conn:
        conn.execute(stmt)

    db = SQLDatabase(engine, sample_rows_in_table_info=2)

    output = db.table_info
    output = output[len(_TEMPLATE_PREFIX) :]
    expected_output = (
        "Table 'user' has columns: {'user_id': ['INTEGER', ['13', '14']], 'user_name': ['VARCHAR(16)', ['Harrison', 'Chase']]}",
        "Table 'company' has columns: {'company_id': ['INTEGER', []], 'company_location': ['VARCHAR', []]}",
    )
    assert sorted(output.split("\n")) == sorted(expected_output)


def test_sql_database_run() -> None:
    """Test that commands can be run successfully and returned in correct format."""
    engine = create_engine("sqlite:///:memory:")
    metadata_obj.create_all(engine)
    stmt = insert(user).values(user_id=13, user_name="Harrison")
    with engine.begin() as conn:
        conn.execute(stmt)
    db = SQLDatabase(engine)
    command = "select user_name from user where user_id = 13"
    output = db.run(command)
    expected_output = "[('Harrison',)]"
    assert output == expected_output


def test_sql_database_run_update() -> None:
    """Test commands which return no rows return an empty string."""
    engine = create_engine("sqlite:///:memory:")
    metadata_obj.create_all(engine)
    stmt = insert(user).values(user_id=13, user_name="Harrison")
    with engine.begin() as conn:
        conn.execute(stmt)
    db = SQLDatabase(engine)
    command = "update user set user_name='Updated' where user_id = 13"
    output = db.run(command)
    expected_output = ""
    assert output == expected_output