tempdb 0.1.0

Create temporary databases for testing.

Spawn temporary PostgreSQL clusters for use in unit tests. This is alpha quality software and the API may change between version.

Usage

The following example shows how to create a temporary database with pytest.

import psycopg2
import pytest

from contextlib import closing
from tempdb import find_postgres_bin_dir, PostgresFactory


@pytest.fixture
def conn():
    # Try to discover a directory where PostgreSQL is installed. If you
    # have installed it in a non-standard location you must replace
    # pg_bin_dir with the path to the binary directory for your
    # installation.
    #
    # It is possible to provide a specific version as an argument if there
    # are multiple versions to choose from. The highest available version
    # is chosen by default.
    pg_bin_dir = find_postgres_bin_dir()
    if pg_bin_dir is None:
        pytest.skip("Unable to locate a PostgreSQL installation")

    # The factory is bound to a particular PostgreSQL version and can be
    # used to create an arbitrary number of clusters
    factory = PostgresFactory(pg_bin_dir)

    # A cluster is an actual running instance of PostgreSQL. By default a
    # cluster doesn't have any databases apart from the defaults. It is
    # possible to create new databases using the method
    # .create_database(name, template=None)
    with closing(factory.create_temporary_cluster()) as cluster:
        tmp_db = cluster.create_database("tmp")
        yield psycopg2.connect(tmp_db.dsn)


def test_create_tables(conn):
    with conn.cursor() as c:
        c.execute("""
            CREATE TABLE test(
                id SERIAL,
                name VARCHAR
            )
        """)
        c.execute("INSERT INTO test(name) VALUES (%s), (%s)", [
            "Abel",
            "Cain",
        ])
        c.execute("SELECT name FROM test ORDER BY id")

        assert [name for name, in c.fetchall()] == [
            "Abel",
            "Cain",
        ]

Changelog

Version 0.1.0

Released on 3rd June, 2019

• Initial release