Testing Helpers

This page describes persista.testing.fixtures, which provides pytest markers to skip tests based on whether an optional dependency is installed.

Prerequisites: You'll need to know a bit of Python and pytest. pytest must be installed to use these fixtures; persista.testing is not a runtime dependency of persista itself.

Overview

Several persista stores and utilities depend on optional packages (aiosqlite, duckdb, faker, lmdb, psycopg, redis, requests, urllib3). persista.testing.fixtures exposes, for each of these, a pair of pytest markers:

• <dep>_available: skip the test unless <dep> is installed
• <dep>_not_available: skip the test if <dep> is installed

For example, lmdb_available and lmdb_not_available are available for the lmdb package, and similarly for the other optional dependencies.

Skipping Tests Based on Optional Dependencies

Use <dep>_available to only run a test when the corresponding package is installed, for example a test that exercises LmdbStore:

from persista.store import LmdbStore
from persista.testing.fixtures import lmdb_available


@lmdb_available
def test_lmdb_store_set_get(tmp_path):
    store = LmdbStore(tmp_path / "db")
    store.set("1", {"value": 42})
    assert store.get("1") == {"value": 42}

Use <dep>_not_available for the opposite case, e.g. verifying that a helpful error is raised when a required optional dependency is missing:

import pytest

from persista.testing.fixtures import lmdb_not_available


@lmdb_not_available
def test_lmdb_store_requires_lmdb():
    with pytest.raises(RuntimeError, match="'lmdb' package is required"):
        from persista.store import LmdbStore

        LmdbStore("/tmp/lmdb_store")

Available Markers

Markers are provided for: aiosqlite, duckdb, faker, lmdb, psycopg, redis, requests, and urllib3. Import them directly from persista.testing.fixtures, for example:

from persista.testing.fixtures import (
    duckdb_available,
    psycopg_available,
    redis_available,
)

API Reference

See the reference documentation for the full API.