arcade-mcp/toolkits/postgres/tests/test_postgres.py

import os
from os import environ
from unittest.mock import MagicMock

import pytest
import pytest_asyncio
from arcade_mcp_server import Context
from arcade_mcp_server.exceptions import RetryableToolError
from arcade_postgres.tools.postgres import (
    DatabaseEngine,
    discover_schemas,
    discover_tables,
    execute_select_query,
    get_table_schema,
)
from sqlalchemy import text
from sqlalchemy.ext.asyncio import create_async_engine

POSTGRES_DATABASE_CONNECTION_STRING = (
    environ.get("TEST_POSTGRES_DATABASE_CONNECTION_STRING")
    or "postgresql://postgres@localhost:5432/postgres"
)


@pytest.fixture
def mock_context():
    context = MagicMock(spec=Context)
    context.get_secret = MagicMock(return_value=POSTGRES_DATABASE_CONNECTION_STRING)
    return context


# before the tests, restore the database from the dump
@pytest_asyncio.fixture(autouse=True)
async def restore_database():
    with open(f"{os.path.dirname(__file__)}/dump.sql") as f:
        engine = create_async_engine(
            POSTGRES_DATABASE_CONNECTION_STRING.replace("postgresql", "postgresql+asyncpg").split(
                "?"
            )[0]
        )
        async with engine.connect() as c:
            queries = f.read().split(";")
            await c.execute(text("BEGIN"))
            for query in queries:
                if query.strip():
                    await c.execute(text(query))
            await c.commit()
        await engine.dispose()


@pytest_asyncio.fixture(autouse=True)
async def cleanup_engines():
    """Clean up database engines after each test to prevent connection leaks."""
    yield
    # Clean up all cached engines after each test
    await DatabaseEngine.cleanup()


@pytest.mark.asyncio
async def test_discover_schemas(mock_context) -> None:
    assert await discover_schemas(mock_context) == ["public"]


@pytest.mark.asyncio
async def test_discover_tables(mock_context) -> None:
    assert await discover_tables(mock_context) == ["messages", "users"]


@pytest.mark.asyncio
async def test_get_table_schema(mock_context) -> None:
    assert await get_table_schema(mock_context, "public", "users") == [
        "id: int (PRIMARY KEY)",
        "name: str (INDEXED)",
        "email: str (INDEXED)",
        "password_hash: str",
        "created_at: datetime",
        "updated_at: datetime",
        "status: str",
    ]

    assert await get_table_schema(mock_context, "public", "messages") == [
        "id: int (PRIMARY KEY)",
        "body: str",
        "user_id: int",
        "created_at: datetime",
        "updated_at: datetime",
    ]


@pytest.mark.asyncio
async def test_execute_select_query(mock_context) -> None:
    assert await execute_select_query(
        mock_context,
        select_clause="id, name, email",
        from_clause="users",
        where_clause="id = 1",
    ) == [
        "(1, 'Alice', 'alice@example.com')",
    ]
    assert await execute_select_query(
        mock_context,
        select_clause="id, name, email",
        from_clause="users",
        order_by_clause="id",
        limit=1,
        offset=1,
    ) == [
        "(2, 'Bob', 'bob@example.com')",
    ]


@pytest.mark.asyncio
async def test_execute_select_query_with_keywords(mock_context) -> None:
    assert await execute_select_query(
        mock_context,
        select_clause="SELECT id, name, email",
        from_clause="FROM users",
        limit=1,
    ) == [
        "(1, 'Alice', 'alice@example.com')",
    ]


@pytest.mark.asyncio
async def test_execute_select_query_with_join(mock_context) -> None:
    assert await execute_select_query(
        mock_context,
        select_clause="u.id, u.name, u.email, m.id, m.body",
        from_clause="users u",
        join_clause="messages m ON u.id = m.user_id",
        limit=1,
    ) == [
        "(1, 'Alice', 'alice@example.com', 1, 'Hello everyone!')",
    ]


@pytest.mark.asyncio
async def test_execute_select_query_with_group_by(mock_context) -> None:
    assert await execute_select_query(
        mock_context,
        select_clause="u.name, COUNT(m.id) AS message_count",
        from_clause="messages m",
        join_clause="users u ON m.user_id = u.id",
        group_by_clause="u.name",
        order_by_clause="message_count DESC",
        limit=2,
    ) == [
        "('Evan', 13)",
        "('Alice', 3)",
    ]


@pytest.mark.asyncio
async def test_execute_select_query_with_no_results(mock_context) -> None:
    # does not raise an error
    assert (
        await execute_select_query(
            mock_context,
            select_clause="id, name, email",
            from_clause="users",
            where_clause="id = 9999999999",
        )
        == []
    )


@pytest.mark.asyncio
async def test_execute_select_query_with_problem(mock_context) -> None:
    # 'foo' is not a valid id
    with pytest.raises(RetryableToolError) as e:
        await execute_select_query(
            mock_context,
            select_clause="*",
            from_clause="users",
            where_clause="id = 'foo'",
        )
    assert "Do not use * in the select clause" in str(e.value)


@pytest.mark.asyncio
async def test_execute_select_query_rejects_non_select(mock_context) -> None:
    with pytest.raises(RetryableToolError) as e:
        await execute_select_query(
            mock_context,
            select_clause="INSERT INTO users (name, email, password_hash) VALUES ('Luigi', 'luigi@example.com', 'password')",
            from_clause="users",
        )
    assert "Only SELECT queries are allowed" in str(e.value)